WO2016031540A1 - Combustion burner and boiler - Google Patents

Combustion burner and boiler Download PDF

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Publication number
WO2016031540A1
WO2016031540A1 PCT/JP2015/072618 JP2015072618W WO2016031540A1 WO 2016031540 A1 WO2016031540 A1 WO 2016031540A1 JP 2015072618 W JP2015072618 W JP 2015072618W WO 2016031540 A1 WO2016031540 A1 WO 2016031540A1
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WO
WIPO (PCT)
Prior art keywords
nozzle
fuel
air
exhaust gas
passage
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Application number
PCT/JP2015/072618
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French (fr)
Japanese (ja)
Inventor
章泰 岡元
和明 橋口
大浦　康二
史裕 中島
宏 藤井
Original Assignee
三菱日立パワーシステムズ株式会社
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Publication of WO2016031540A1 publication Critical patent/WO2016031540A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C99/00—Subject-matter not provided for in other groups of this subclass
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/20—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone
    • F23D14/22—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L7/00—Supplying non-combustible liquids or gases, other than air, to the fire, e.g. oxygen, steam

Definitions

  • the present invention relates to a combustion burner which forms a flame by injecting a fluid fuel and air and injecting the mixture, and a boiler using the combustion burner.
  • a typical boiler has a hollow furnace in the vertical direction, and a plurality of combustion burners are arranged along the circumferential direction on the furnace wall, and are arranged in multiple stages in the vertical direction. ing.
  • the combustion burner forms a flame by blowing gas fuel or oil fuel and air into the furnace, and can burn in the furnace.
  • a flue is connected to the upper part of the furnace, and a superheater, a reheater, a economizer, etc. for recovering the heat of the exhaust gas are provided in the flue, and it was generated by the combustion in the furnace Heat exchange takes place between the exhaust gas and the water and steam can be generated.
  • TM burner As a combustion burner used in this boiler, there is one called a TM burner.
  • This TM burner is a combination of premixed combustion and diffusion combustion. Then, the concentration of NOx generated when the fuel burns varies with the ratio of air to fuel (air ratio). In this case, the concentration of NOx generated changes depending on the air ratio (air / fuel) between the premixed combustion and the diffusion combustion. Therefore, the TM burner can reduce the generation amount of NOx by combining the premixed combustion and the diffusion combustion.
  • combustion burners examples include those described in Patent Documents 1 and 2 below.
  • a diffusion flame is formed by injecting air and fuel to the central portion and igniting, and the primary air is injected to the outside thereof and the fuel and the secondary air are injected and ignited.
  • Premixed combustion forms a premixed flame by injecting and igniting an air-fuel mixture in which fuel and secondary air are mixed. Therefore, when the ratio of fuel increases and the air ratio moves to 1.0 due to variations in the amount of supplied fuel or the amount of supplied air, the premixed flame that has been ignited by a predetermined distance from the nozzle tip is a nozzle As the tip approaches, the nozzle tip may be thermally damaged.
  • the present invention solves the above-mentioned problems, and provides a combustion burner and a boiler that reduce the amount of NOx generation by preventing the heat damage of the nozzle tip by making the mixing ratio of fluid fuel and air a proper ratio.
  • the purpose is to
  • the combustion burner of the present invention comprises an air nozzle for injecting air, a first fuel nozzle for injecting fluid fuel outside the air nozzle, and a primary fuel nozzle outside the first fuel nozzle.
  • the fluid fuel injected from the first fuel nozzle mixes with the air injected from the air nozzle, mixes with the primary air injected from the primary air nozzle, and forms a diffusion flame by igniting.
  • the fluid fuel injected from the second fuel nozzle is mixed with the recirculating exhaust gas in the recirculating exhaust gas nozzle and then injected, mixed with the secondary air injected from the secondary air nozzle, and pre-ignitioned by ignition. Form a mixed flame. Therefore, the NOx generation amount can be reduced by setting the mixing ratio of the fluid fuel and air to an appropriate ratio.
  • the fluid fuel injected from the second fuel nozzle is mixed with the recirculation exhaust gas, mixed with the secondary air, and ignited, so that the premixed flame is slowly burned in the area away from the nozzle tip. As a result, thermal damage to the nozzle tip can be prevented.
  • the second fuel nozzle is characterized in that the fluid fuel is injected into the passage of the recirculation exhaust gas nozzle and the passage of the secondary air nozzle.
  • the second fuel nozzle is characterized in that 30% to 40% of the fluid fuel of a fuel amount preset in the passage of the recirculation exhaust gas nozzle is injected.
  • the second fuel nozzle is characterized in that the entire amount of fluid fuel is injected into the passage of the recirculation exhaust gas nozzle.
  • thermal damage to the nozzle tip can be properly prevented by injecting all of the fluid fuel into the passage of the recirculation exhaust gas nozzle, and by keeping the flame away from the nozzle tip.
  • an air nozzle for injecting air a first fuel nozzle for injecting fluid fuel outside the air nozzle, and a primary for injecting primary air outside the first fuel nozzle
  • a recirculated exhaust gas nozzle for spouting the recirculated exhaust gas.
  • the fluid fuel injected from the first fuel nozzle mixes with the air injected from the air nozzle, mixes with the primary air injected from the primary air nozzle, and forms a diffusion flame by igniting. Further, the fluid fuel injected from the second fuel nozzle is mixed with the secondary air and the recirculated exhaust gas in the passage of the secondary air nozzle, and then injected and ignited to form a premixed flame. Therefore, the NOx generation amount can be reduced by setting the mixing ratio of the fluid fuel and air to an appropriate ratio.
  • the fuel injected from the second fuel nozzle is mixed with the secondary air and the recirculated exhaust gas and ignited, so that the premixed flame slowly burns in a region separated from the nozzle tip, Thermal damage to the nozzle tip can be prevented.
  • the recirculation exhaust gas nozzle is disposed outside the secondary air nozzle and ejects the recirculation exhaust gas to the outside of the secondary air, and the recirculation exhaust gas in the passage of the secondary air nozzle It is characterized by spouting.
  • the fluid fuel injected from the second fuel nozzle is injected after being mixed with the secondary air and a part of the recirculated exhaust gas in the passage of the secondary air nozzle, whereby a part of the recirculated exhaust gas is a fluid fuel After mixing with this, it will be injected from the tip of the nozzle and ignited, and heat damage to the tip of the nozzle can be properly prevented by keeping the flame away from the tip of the nozzle while securing sufficient ignitability. .
  • fluid fuel and air are burned in a hollow furnace and heat exchange is performed in the furnace to recover heat, and the combustion burner is disposed on the furnace wall It is characterized by
  • NOx can be obtained by making the mixing ratio of the fluid fuel and the air appropriate.
  • the amount of generation can be reduced, and thermal damage to the nozzle tip can be prevented.
  • FIG. 1 is a cross-sectional view showing the combustion burner of the first embodiment.
  • FIG. 2 is a front view of the combustion burner.
  • FIG. 3 is a schematic configuration diagram showing a boiler of the first embodiment.
  • FIG. 4 is a graph showing the relationship between the air ratio of the combustion burner in which diffusion combustion and premixed combustion are combined and the NOx generation amount.
  • FIG. 5 is a cross-sectional view showing a combustion burner of a second embodiment.
  • FIG. 6 is a cross-sectional view showing a combustion burner of a third embodiment.
  • FIG. 3 is a schematic configuration diagram showing a boiler of the first embodiment.
  • the boiler of the first embodiment can use gas fuel (natural gas) as fluid fuel, inject this gas fuel and air by a combustion burner, burn it in a furnace, and recover the heat generated by this combustion It is a boiler.
  • gas fuel natural gas
  • the boiler of the first embodiment can use not only fluid fuel but also heavy oil (or light oil, slurry of coal, etc.) as fuel, and this heavy oil can be injected by a combustion burner and burned in a furnace.
  • the boiler 10 is a conventional boiler, and includes a furnace 11 and a combustion device 12.
  • the furnace 11 has a hollow shape of a square cylinder and is installed along the vertical direction, and the combustion apparatus 12 is provided at the lower part of the furnace wall constituting the furnace 11.
  • the combustion device 12 has a plurality of combustion burners 21 mounted on the furnace wall.
  • the combustion burners 21 are, for example, four arranged at equal intervals along the circumferential direction, for example, three sets, that is, three stages along the vertical direction. It is arranged.
  • the arrangement location and the number of the combustion burners 21 are not limited to this.
  • Each combustion burner 21 is connected to a fuel supply source 23 via a fuel supply pipe 22, and the fuel supply pipe 22 is provided with a flow control valve 24 capable of adjusting a fuel supply amount.
  • a flow control valve 24 capable of adjusting a fuel supply amount.
  • an air box 25 is provided at the mounting position of each combustion burner 21.
  • One end of an air duct 26 is connected to the air box 25.
  • the air duct 26 is connected to the other end.
  • a blower 27 is mounted.
  • each combustion burner 21 is supplied with gaseous fuel from the fuel supply source 23 through the fuel supply pipe 22.
  • the combustion air heated from the air duct 26 in heat exchange with the exhaust gas is supplied to the air box 25. Therefore, the combustion burner 21 can form a flame in the furnace 11 by injecting gas fuel into the furnace 11 and injecting combustion air into the furnace 11 to ignite the same.
  • the flue 31 is connected to the upper part of the furnace 11 and superheaters (super heaters) 32, 33 for recovering the heat of the exhaust gas as a convection heat transfer part (heat recovery part) are connected to the flue 31.
  • Heaters (reheaters) 34, 35 and economizers (economizers) 36, 37, 38 are provided, and heat exchange is performed between the exhaust gas generated by the combustion in the furnace 11 and water.
  • the flue 31 is connected downstream with an exhaust gas pipe 39 through which the exhaust gas subjected to heat exchange is discharged.
  • the exhaust gas pipe 39 is provided with a NOx removal device, an electrostatic precipitator, an induction fan, and a desulfurization device, and a chimney is provided at the downstream end.
  • water supplied from a water supply pump (not shown) is preheated by economizers 36, 37, 38 and then supplied to a steam drum (not shown) and supplied to water pipes (not shown) of the furnace wall. It is heated to become saturated steam and is fed to a steam drum (not shown). Furthermore, saturated steam of a steam drum (not shown) is introduced into the superheaters 32, 33 and is overheated by the combustion gas. The superheated steam generated by the superheaters 32 and 33 is supplied to a power plant (for example, a turbine etc.) not shown. Further, the steam taken out in the middle of the expansion process in the turbine is introduced into the reheaters 34, 35, and is again overheated and returned to the turbine.
  • the furnace 11 was demonstrated as a drum type (steam drum), it is not limited to this structure.
  • the exhaust gas that has passed through the economizers 36, 37, 38 of the flue 31 is subjected to exhaust gas pipe 39 with a NOx removal device (not shown) to remove harmful substances such as NOx by the catalyst and particulate matter with an electrostatic precipitator Is removed and the sulfur content is removed by the desulfurization device, and then discharged to the atmosphere from the chimney.
  • NOx removal device not shown
  • FIG. 1 is a cross-sectional view showing the combustion burner of the first embodiment
  • FIG. 2 is a front view of the combustion burner.
  • the combustion burner 21 includes an air nozzle 41 disposed from the center (axial center O) side to the outside, a first fuel nozzle 42, and a primary air nozzle 43, 2.
  • a secondary air nozzle 44, a recirculating exhaust gas nozzle 45, and a second fuel nozzle 46 are provided.
  • the central axis 51 has a cylindrical shape, and the cylindrical tube 52 is provided at a predetermined distance outside the outer peripheral surface of the central axis 51 to configure the air nozzle 41 between the central axis 51 and the cylindrical tube 52.
  • the passage 41a is formed along the axial direction.
  • the central shaft 51 is provided with an ignition unit 61 at its tip end, and a ring-shaped flame stabilizer 62 is provided on the outer peripheral surface so as to protrude toward the passage 41 a.
  • the cylindrical tubes 52 are provided with a cylindrical tube 53 spaced apart from the outer peripheral surface by a predetermined distance outside, and a plurality (six in this embodiment) of the cylindrical tubes 52 and 53 at predetermined intervals in the circumferential direction.
  • the first fuel nozzle 42 is disposed, and a passage 42a is formed in the inside along the axial direction.
  • the cylindrical tube 53 is provided with the cylindrical tube 54 at a predetermined distance away from the outer peripheral surface so that the passage 43a constituting the primary air nozzle 43 between the respective cylindrical tubes 53 and 54 extends in the axial direction. It is formed.
  • the cylindrical pipe 54 is provided with a cylindrical pipe 55 spaced apart from the outer peripheral surface by a predetermined distance, so that a passage 44 a constituting the secondary air nozzle 44 is formed along the axial direction between the cylindrical pipes 54 and 55. It is done.
  • the cylindrical pipe 55 is provided with a cylindrical pipe 56 spaced apart from the outer peripheral surface by a predetermined distance so that a passage 45a constituting the recirculation exhaust gas nozzle 45 is formed along the axial direction between the respective cylindrical pipes 55, 56. It is done.
  • a plurality of (four in the present embodiment) second fuel nozzles 46 are provided at equal intervals in the circumferential direction of the cylindrical tubes 55 and 56. Each second fuel nozzle 46 penetrates from the outside of the cylindrical tube 56 to the cylindrical tube 55, and is disposed in the passage 45a.
  • the air nozzle 41 can supply air to the passage 41a and can jet the air forward.
  • the first fuel nozzle 42 can supply gas fuel to the passage 42 a and inject the gas fuel (weak fuel) forward on the outside of the air nozzle 41.
  • the primary air nozzle 43 can supply the primary air to the passage 43 a and inject the primary air forward on the outside of the first fuel nozzle 42.
  • the secondary air nozzle 44 can supply the secondary air to the passage 44 a and can jet the secondary air forward on the outside of the primary air nozzle 43.
  • the recirculation exhaust gas nozzle 45 can supply the recirculation exhaust gas to the passage 45 a and can jet the recirculation exhaust gas forward on the outside of the secondary air nozzle 44.
  • the second fuel nozzle 46 can inject gas fuel (conch fuel) into the passage 45 a of the recirculation exhaust gas nozzle 45 to which the recirculation exhaust gas is supplied.
  • the second fuel nozzle 46 injects the entire amount of gas fuel into the passage 45 a of the recirculation exhaust gas nozzle 45.
  • air is represented by a white-blown arrow
  • fuel is represented by a hatched arrow
  • recirculated exhaust gas is represented by a dotted arrow.
  • the air nozzle 41 jets air forward, and the first fuel nozzle 42 jets gas fuel forward. Then, since the air becomes a swirling flow toward the center (axial center O) by the flame holder 62, the gas fuel is also attracted to the central (axial center O) side by the swirling flow. Therefore, the gas fuel and the air are mixed and ignited by the igniter 61 to form a diffusion flame (fuel rich flame) A. Then, the primary air nozzle 43 jets the primary air toward the front, and the secondary air nozzle 44 jets the secondary air toward the front. Further, the recirculation exhaust gas nozzle 45 injects the recirculation exhaust gas forward, and the second fuel nozzle 46 injects the gas fuel into the passage 45 a of the recirculation exhaust gas nozzle 45.
  • the recirculation exhaust gas in which the secondary air injected to the front and the gas fuel are mixed is mixed in front of the nozzles 44 and 45, and the diffusion flame A is ignited as a spark and a premixed flame (fuel lean flame) B is It is formed.
  • gas fuel is injected into the passage 45 a of the recirculation exhaust gas nozzle 45.
  • the recirculated exhaust gas is generated by combustion of gas fuel and air, contains almost no air, and is difficult to ignite even when mixed with gas fuel. Therefore, when the recirculation exhaust gas containing the gas fuel is injected from the recirculation exhaust gas nozzle 45 and the secondary air is injected from the second fuel nozzle 46, the recirculation exhaust gas containing the gas fuel and the secondary air The air-fuel mixture is difficult to ignite, and the premixed flame B is formed in a front region spaced apart from the tip of the nozzles 44 and 45 by a predetermined distance. Therefore, the premixed flame B does not approach the tips of the nozzles 44 and 45, and the tips of the nozzles 44 and 45 are not thermally damaged.
  • the combustion burner 21 of the first embodiment is a combination of premixed combustion and diffusion combustion.
  • FIG. 4 is a graph showing the relationship between the air ratio of the combustion burner in which diffusion combustion and premixed combustion are combined and the NOx generation amount.
  • the concentration of NOx generated when the gas fuel burns varies with the ratio of air to fuel (air ratio).
  • the concentration of NOx generated changes depending on the air ratio (air / fuel) between the premixed combustion and the diffusion combustion.
  • premixed combustion premixed flame B
  • the concentration of NOx is low in the high air ratio (more air) region or the low air ratio (less air) region, the air ratio is 1.0 (theoretical air) Ratio) is high.
  • the concentration of NOx is low in the region where the air ratio is low (less air) and is low in the region where the air ratio is high (more air).
  • the position b where the air ratio is high and the concentration of NOx is low in premixed combustion and the position a where the air ratio is low and concentration of NOx is low in diffusion combustion
  • the dotted line connected as a whole and based on the position c where the air ratio is higher than 1.0 (theoretical air ratio)
  • the air nozzle 41 for injecting air, the first fuel nozzle 42 for injecting gas fuel outside the air nozzle 41, and the outside of the first fuel nozzle 42 A primary air nozzle 43 that jets primary air, a secondary air nozzle 44 that jets secondary air outside the primary air nozzle 43, and a recirculation that jets recirculated exhaust gas outside the secondary air nozzle 44
  • An exhaust gas nozzle 45 and a second fuel nozzle 46 for injecting gas fuel into the passage 45 a of the recirculation exhaust gas nozzle 45 are provided.
  • the gaseous fuel injected from the first fuel nozzle 42 mixes with the air injected from the air nozzle 41 and mixes with the primary air injected from the primary air nozzle 43, and is ignited by igniting it.
  • the gas fuel injected from the second fuel nozzle 46 is injected after being mixed with the recirculated exhaust gas in the recirculated exhaust gas nozzle 45, mixed with the secondary air injected from the secondary air nozzle 44, and ignited Form a premixed flame B. Therefore, the NOx generation amount can be reduced by setting the mixing ratio of the gas fuel to the air to an appropriate ratio.
  • the gaseous fuel injected from the second fuel nozzle 46 is mixed with the recirculated exhaust gas, mixed with the secondary air, and ignited, in a region where the premixed flame B is separated from the nozzle tip. It will burn slowly and can prevent the heat damage of the nozzle tip.
  • the second fuel nozzle 46 injects the entire amount of gas fuel into the passage 45 a of the recirculation exhaust gas nozzle 45. Therefore, by injecting all of the gas fuel into the passage 45a of the recirculation exhaust gas nozzle 45, heat damage to the nozzle tip can be properly prevented by keeping the flame away from the nozzle tip.
  • the gas fuel and the air are burned in the hollow furnace 11 and heat exchange is performed in the furnace 11 to recover the heat.
  • a burner 21 is disposed. Therefore, by setting the mixing ratio of gas fuel to air to an appropriate ratio in the combustion burner 21, it is possible to reduce the amount of NOx generation and to prevent the thermal damage of the nozzle tip, and as a result, the boiler The efficiency can be improved and the life of the boiler can be extended.
  • FIG. 5 is a cross-sectional view showing a combustion burner of a second embodiment.
  • the members having the same functions as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.
  • the combustion burner 71 is an air nozzle 41 disposed outward from the center (axial center O) side, a first fuel nozzle 42, and a primary air nozzle 43. , A secondary air nozzle 44, a recirculation exhaust gas nozzle 45, and a second fuel nozzle 72.
  • a plurality of second fuel nozzles 72 are provided at equal intervals in the circumferential direction of the cylindrical tubes 54, 55, 56. Each second fuel nozzle 72 penetrates from the outside of the cylindrical tube 56 to the cylindrical tube 54, and is disposed in the passages 44a and 45a.
  • the air nozzle 41 can supply air to the passage 41a and can jet the air forward.
  • the first fuel nozzle 42 can supply gas fuel to the passage 42 a and inject the gas fuel (weak fuel) forward on the outside of the air nozzle 41.
  • the primary air nozzle 43 can supply the primary air to the passage 43 a and inject the primary air forward on the outside of the first fuel nozzle 42.
  • the secondary air nozzle 44 can supply the secondary air to the passage 44 a and can jet the secondary air forward on the outside of the primary air nozzle 43.
  • the recirculation exhaust gas nozzle 45 can supply the recirculation exhaust gas to the passage 45 a and can jet the recirculation exhaust gas forward on the outside of the secondary air nozzle 44.
  • the second fuel nozzle 72 injects the gas fuel (conch fuel) into both the passage 44a of the secondary air nozzle 44 to which the secondary air is supplied and the passage 45a of the recirculation exhaust gas nozzle 45 to which the recirculated exhaust gas is supplied. can do.
  • the second fuel nozzle 72 injects 30% to 40% of gaseous fuel into the passage 45a of the recirculation exhaust gas nozzle 45 in advance. That is, 30% to 40% of the gas fuel injected by the second fuel nozzle 72 is injected into the passage 45a of the recirculation exhaust gas nozzle 45, and the remaining 60% to 70% of the gas fuel is injected into the secondary air nozzle 44. To the passage 44a of the
  • the air nozzle 41 jets air forward, and the first fuel nozzle 42 jets gas fuel forward. Then, since the air becomes a swirling flow toward the center (axial center O) by the flame holder 62, the gas fuel is also attracted to the central (axial center O) side by the swirling flow. Therefore, the gas fuel and the air are mixed and ignited by the igniter 61 to form a diffusion flame (fuel rich flame) A. Then, the primary air nozzle 43 jets the primary air forward, the secondary air nozzle 44 jets the secondary air forward, and the recirculation exhaust gas nozzle 45 directs the recirculation exhaust gas Inject.
  • the second fuel nozzle 72 injects the gas fuel into the passage 44 a of the secondary air nozzle 44 and the passage 45 a of the recirculation exhaust gas nozzle 45. Therefore, the gas fuel and the secondary air are mixed in the passage 44a of the secondary air nozzle 44, and further, the gas fuel in the recirculated exhaust gas is mixed in the front, and the diffusion flame A is ignited as a spark to mix the premixed flame (fuel Lean flame) B is formed.
  • gaseous fuel is injected into the passage 44 a of the secondary air nozzle 44 and the passage 45 a of the recirculation exhaust gas nozzle 45.
  • the recirculated exhaust gas is generated by combustion of gas fuel and air, contains almost no air, and is difficult to ignite even when mixed with gas fuel. Therefore, when the recirculation exhaust gas containing the gas fuel is injected from the recirculation exhaust gas nozzle 45 and the mixture of the secondary air and the gas fuel is injected from the second fuel nozzle 72, the recirculation containing the gas fuel is performed.
  • the exhaust gas and the air-fuel mixture are not easily ignited, and the premixed flame B is formed in a front region separated from the tip of the nozzles 44 and 45 by a predetermined distance. Therefore, the premixed flame B does not approach the tips of the nozzles 44 and 45, and the tips of the nozzles 44 and 45 are not thermally damaged.
  • the second fuel nozzle 72 for injecting the gas fuel is provided in the passage 44 a of the secondary air nozzle 44 and the passage 45 a of the recirculation exhaust gas nozzle 45.
  • the gas fuel into the passage 44a of the secondary air nozzle 44 and the passage 45a of the recirculation exhaust gas nozzle 45, a part of the gas fuel is mixed with the recirculation exhaust gas, and the remaining gas fuel is mixed with the secondary air.
  • the nozzle tip is injected and ignited, and heat damage to the nozzle tip can be properly prevented by keeping the flame away from the nozzle tip while securing sufficient ignition performance.
  • the second fuel nozzle 72 injects 30% to 40% of gaseous fuel to the passage 45 a of the recirculating exhaust gas nozzle 45 in advance. Therefore, by setting the ratio of the gas fuel injected into the passage 45a of the recirculating exhaust gas nozzle 45 to the gas fuel injected into the passage 44a of the secondary air nozzle 44 to an appropriate value, sufficient ignitability and thermal damage to the nozzle tip Can be achieved at the same time.
  • FIG. 6 is a cross-sectional view showing a combustion burner of a third embodiment.
  • the members having the same functions as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.
  • the combustion burner 81 has an air nozzle 41, a first fuel nozzle 42, and a primary air nozzle 43 disposed outward from the center (axial center O) side. , A secondary air nozzle 44, a recirculation exhaust gas nozzle 45, and a second fuel nozzle 82.
  • the cylindrical pipe 54 is provided with a cylindrical pipe 55 spaced apart from the outer peripheral surface by a predetermined distance, so that a passage 44 a constituting the secondary air nozzle 44 is formed along the axial direction between the cylindrical pipes 54 and 55. It is done.
  • the cylindrical pipe 55 is provided with a cylindrical pipe 56 spaced apart from the outer peripheral surface by a predetermined distance so that a passage 45a constituting the recirculation exhaust gas nozzle 45 is formed along the axial direction between the respective cylindrical pipes 55, 56. It is done.
  • the cylindrical tube 44 is formed with an opening 83 communicating the passages 44a and 45a.
  • the openings 83 may be continuous in the circumferential direction, or a plurality of the openings 83 may be provided at predetermined intervals in the circumferential direction.
  • a passage may be provided to connect the passages 44a and 45a.
  • a plurality of second fuel nozzles 82 are provided at equal intervals in the circumferential direction of the cylindrical tubes 54 and 55. Each second fuel nozzle 82 penetrates from the outside of the cylindrical tube 55 to the cylindrical tube 54 and is disposed in the passage 44 a.
  • the air nozzle 41 can supply air to the passage 41a and can jet the air forward.
  • the first fuel nozzle 42 can supply gas fuel to the passage 42 a and inject the gas fuel (weak fuel) forward on the outside of the air nozzle 41.
  • the primary air nozzle 43 can supply the primary air to the passage 43 a and inject the primary air forward on the outside of the first fuel nozzle 42.
  • the secondary air nozzle 44 can supply the secondary air to the passage 44 a and can jet the secondary air forward on the outside of the primary air nozzle 43.
  • the recirculation exhaust gas nozzle 45 supplies recirculation exhaust gas to the passage 45 a and injects the recirculation exhaust gas forward toward the outside of the secondary air nozzle 44, and part of the recirculation exhaust gas nozzle 45 in the passage 44 a of the secondary air nozzle 44. It can be injected.
  • the second fuel nozzle 82 can inject gas fuel (conch fuel) into the passage 44 a of the secondary air nozzle 44 to which the secondary air and the recirculated exhaust gas are supplied.
  • the air nozzle 41 jets air forward, and the first fuel nozzle 42 jets gas fuel forward. Then, since the air becomes a swirling flow toward the center (axial center O) by the flame holder 62, the gas fuel is also attracted to the central (axial center O) side by the swirling flow. Therefore, the gas fuel and the air are mixed and ignited by the igniter 61 to form a diffusion flame (fuel rich flame) A. Then, the primary air nozzle 43 jets the primary air toward the front, and the secondary air nozzle 44 jets the secondary air toward the front. Further, the recirculation exhaust gas nozzle 45 jets the recirculation exhaust gas forward, and injects part of the recirculation exhaust gas into the passage 44 a of the secondary air nozzle 44.
  • the second fuel nozzle 82 injects the gas fuel into the passage 44 a of the secondary air nozzle 44. Therefore, the secondary air and the gas fuel injected forward are mixed in front of the nozzles 44 and 45, and the diffusion flame A is ignited as a flame to form a premixed flame (fuel lean flame) B.
  • the recirculated exhaust gas is injected in advance into the passage 44 a of the secondary air nozzle 44.
  • the recirculated exhaust gas is generated by combustion of gas fuel and air, contains almost no air, and is difficult to ignite even when mixed with gas fuel. Therefore, when the gas fuel is injected to the secondary air containing the recirculation exhaust gas and the secondary air and the recirculation exhaust gas and the gas fuel are injected from the second fuel nozzle 82, the gas fuel and the secondary air are injected by the recirculation exhaust gas.
  • the premixed flame B is formed in a front region separated from the tip of the nozzles 44 and 45 by a predetermined distance. Therefore, the premixed flame B does not approach the tips of the nozzles 44 and 45, and the tips of the nozzles 44 and 45 are not thermally damaged.
  • the air nozzle 41 for injecting air As described above, in the combustion burner of the third embodiment, the air nozzle 41 for injecting air, the first fuel nozzle 42 for injecting gas fuel outside the air nozzle 41, and the outside of the first fuel nozzle 42
  • the primary air nozzle 43 injecting primary air
  • the secondary air nozzle 44 injecting secondary air outside the primary air nozzle 43
  • the recirculation exhaust gas nozzle 45 injects the fuel gas into the passage 44 a of the secondary air nozzle 44
  • the second fuel nozzle 82 injects the gas fuel into the passage 44 a of the secondary air nozzle 44.
  • the gaseous fuel injected from the first fuel nozzle 42 mixes with the air injected from the air nozzle 41 and mixes with the primary air injected from the primary air nozzle 43, and is ignited by igniting it.
  • the gas fuel injected from the second fuel nozzle 82 is injected to the mixture of the secondary air and the recirculated exhaust gas in the passage 44a of the secondary air nozzle 44, mixed with the secondary air, and ignited.
  • the gaseous fuel injected from the second fuel nozzle 82 is ignited after being mixed with the secondary air and the recirculated exhaust gas, so that the premixed flame B burns slowly in a region separated from the nozzle tip. As a result, thermal damage to the nozzle tip can be prevented.
  • the air nozzle 41, the first fuel nozzle 42, the primary air nozzle 43, and the secondary air nozzle 44 are obtained by combining a plurality of cylindrical tubes 52, 53, 54, 55, and 56 having different diameters.
  • the recirculation exhaust gas nozzle 45 and the second fuel nozzles 46, 72, 82 are configured, the present invention is not limited to this configuration. It may replace with a cylindrical pipe and may provide a square cylindrical pipe (polygonal cylindrical pipe). Further, as in Patent Document 2, an air nozzle and a first fuel nozzle are provided at the center, and a secondary air nozzle and a second fuel nozzle are provided at the upper and lower portions, and the primary air nozzle and the recirculation exhaust gas nozzle are interposed therebetween. You may provide.
  • the recirculation exhaust gas is effectively used to prevent the premixed flame ignited in front of the nozzle tip from approaching the nozzle tip and causing thermal damage.
  • the order of mixing the next air and the recirculated exhaust gas is not limited to the embodiment described above, and may be set as appropriate.
  • the recirculation exhaust gas may be injected into the mixture of the second fuel and the secondary air.

Abstract

　A combustion burner and boiler, which are provided with an air nozzle (41) for spraying air, a first fuel nozzle (42) for spraying a gas fuel on the outside of the air nozzle (41), a primary air nozzle (43) for spraying primary air on the outside of the first fuel nozzle (42), a secondary air nozzle (44) for spraying secondary air on the outside of the primary air nozzle (43), a recirculated exhaust gas nozzle (45) for spraying recirculated exhaust gas on the outside of the secondary air nozzle (44), and a second fuel nozzle (46) for spraying a gas fuel onto the passage (45a) of the recirculated exhaust gas nozzle (45), whereby the mixture ratio of the liquid fuel and air is brought to an optimal ratio, the amount of NOx generated is reduced, and heat damage to the nozzle tip section is prevented.

Description

燃焼バーナ及びボイラCombustion burner and boiler
　本発明は、流体燃料と空気とを混合して噴出することにより火炎を形成する燃焼バーナ、この燃焼バーナを使用するボイラに関するものである。 The present invention relates to a combustion burner which forms a flame by injecting a fluid fuel and air and injecting the mixture, and a boiler using the combustion burner.
　一般的なボイラは、中空形状をなして鉛直方向に設置される火炉を有し、この火炉壁に複数の燃焼バーナが周方向に沿って配設されると共に、上下方向に複数段にわたって配置されている。この燃焼バーナは、ガス燃料や油燃料と空気を火炉内に吹き込むことで火炎を形成し、この火炉内で燃焼可能となっている。そして、この火炉は、上部に煙道が連結され、この煙道に排ガスの熱を回収するための過熱器、再熱器、節炭器などが設けられており、火炉での燃焼により発生した排ガスと水との間で熱交換が行われ、蒸気を生成することができる。 A typical boiler has a hollow furnace in the vertical direction, and a plurality of combustion burners are arranged along the circumferential direction on the furnace wall, and are arranged in multiple stages in the vertical direction. ing. The combustion burner forms a flame by blowing gas fuel or oil fuel and air into the furnace, and can burn in the furnace. A flue is connected to the upper part of the furnace, and a superheater, a reheater, a economizer, etc. for recovering the heat of the exhaust gas are provided in the flue, and it was generated by the combustion in the furnace Heat exchange takes place between the exhaust gas and the water and steam can be generated.
　このボイラで使用される燃焼バーナとして、ＴＭバーナと呼ばれるものがある。このＴＭバーナは、予混合燃焼と拡散燃焼とを組み合わせたものである。そして、燃料が燃焼したときに発生するＮＯｘの濃度は、空気と燃料との比（空気比）により変化する。この場合、予混合燃焼と拡散燃焼とでは、空気比（空気／燃料）に応じて発生するＮＯｘの濃度が変化する。そのため、ＴＭバーナは、予混合燃焼と拡散燃焼とを組み合わせることで、ＮＯｘの発生量を低減させることができる。 As a combustion burner used in this boiler, there is one called a TM burner. This TM burner is a combination of premixed combustion and diffusion combustion. Then, the concentration of NOx generated when the fuel burns varies with the ratio of air to fuel (air ratio). In this case, the concentration of NOx generated changes depending on the air ratio (air / fuel) between the premixed combustion and the diffusion combustion. Therefore, the TM burner can reduce the generation amount of NOx by combining the premixed combustion and the diffusion combustion.
　このような燃焼バーナとしては、例えば、下記特許文献１、２に記載されたものがある。 Examples of such combustion burners include those described in Patent Documents 1 and 2 below.
特開昭５０－１１９３３２号公報Japanese Patent Application Laid-Open No. 50-119332 特開平０７－１５８８１８号公報JP 07-158818 A
　ところで、従来の燃焼バーナは、中央部に空気と燃料を噴射して着火することで拡散火炎を形成し、その外側に１次空気を噴射すると共に燃料と２次空気を噴射して着火することで予混合火炎をする。予混合燃焼は、燃料と２次空気とを混合した混合気を噴射して着火することで予混合火炎を形成するものである。そのため、燃料供給量や空気供給量のばらつきにより、燃料の割合が多くなって空気比が１．０側に移動したとき、ノズル先端部から所定距離だけ前方で着火していた予混合火炎がノズル先端部に近づき、このノズル先端部が熱損傷してしまうおそれがある。 By the way, in the conventional combustion burner, a diffusion flame is formed by injecting air and fuel to the central portion and igniting, and the primary air is injected to the outside thereof and the fuel and the secondary air are injected and ignited. Premix flame with. Premixed combustion forms a premixed flame by injecting and igniting an air-fuel mixture in which fuel and secondary air are mixed. Therefore, when the ratio of fuel increases and the air ratio moves to 1.0 due to variations in the amount of supplied fuel or the amount of supplied air, the premixed flame that has been ignited by a predetermined distance from the nozzle tip is a nozzle As the tip approaches, the nozzle tip may be thermally damaged.
　本発明は、上述した課題を解決するものであり、流体燃料と空気の混合比を適正比にすることでＮＯｘ発生量を低減すると共にノズル先端部の熱損傷を防止する燃焼バーナ及びボイラを提供することを目的とする。 The present invention solves the above-mentioned problems, and provides a combustion burner and a boiler that reduce the amount of NOx generation by preventing the heat damage of the nozzle tip by making the mixing ratio of fluid fuel and air a proper ratio. The purpose is to
　上記の目的を達成するための本発明の燃焼バーナは、空気を噴射する空気ノズルと、前記空気ノズルの外側で流体燃料を噴射する第１燃料ノズルと、前記第１燃料ノズルの外側で１次空気を噴射する１次空気ノズルと、前記１次空気ノズルの外側で２次空気を噴射する２次空気ノズルと、前記２次空気ノズルの外側で再循環排ガスを噴出する再循環排ガスノズルと、前記再循環排ガスノズルの通路に流体燃料を噴射する第２燃料ノズルと、を有することを特徴とするものである。 In order to achieve the above object, the combustion burner of the present invention comprises an air nozzle for injecting air, a first fuel nozzle for injecting fluid fuel outside the air nozzle, and a primary fuel nozzle outside the first fuel nozzle. A primary air nozzle for jetting air, a secondary air nozzle for jetting secondary air outside the primary air nozzle, and a recirculating exhaust gas nozzle for jetting recirculation exhaust gas outside the secondary air nozzle; And a second fuel nozzle for injecting fluid fuel into the passage of the recirculation exhaust gas nozzle.
　従って、第１燃料ノズルから噴射された流体燃料は、空気ノズルから噴射された空気と混合すると共に１次空気ノズルから噴射された１次空気と混合し、着火することで拡散火炎を形成する。また、第２燃料ノズルから噴射された流体燃料は、再循環排ガスノズル内の再循環排ガスと混合した後に噴射され、２次空気ノズルから噴射された２次空気と混合し、着火することで予混合火炎を形成する。そのため、流体燃料と空気との混合比を適正比にすることでＮＯｘ発生量を低減することができる。また、このとき、第２燃料ノズルから噴射された流体燃料は、再循環排ガスと混合した後に２次空気と混合して着火することで、予混合火炎がノズル先端部から離間した領域で緩慢燃焼することとなり、ノズル先端部の熱損傷を防止することができる。 Therefore, the fluid fuel injected from the first fuel nozzle mixes with the air injected from the air nozzle, mixes with the primary air injected from the primary air nozzle, and forms a diffusion flame by igniting. The fluid fuel injected from the second fuel nozzle is mixed with the recirculating exhaust gas in the recirculating exhaust gas nozzle and then injected, mixed with the secondary air injected from the secondary air nozzle, and pre-ignitioned by ignition. Form a mixed flame. Therefore, the NOx generation amount can be reduced by setting the mixing ratio of the fluid fuel and air to an appropriate ratio. Also, at this time, the fluid fuel injected from the second fuel nozzle is mixed with the recirculation exhaust gas, mixed with the secondary air, and ignited, so that the premixed flame is slowly burned in the area away from the nozzle tip. As a result, thermal damage to the nozzle tip can be prevented.
　本発明の燃焼バーナでは、前記第２燃料ノズルは、前記再循環排ガスノズルの通路と前記２次空気ノズルの通路に流体燃料を噴射することを特徴としている。 In the combustion burner of the present invention, the second fuel nozzle is characterized in that the fluid fuel is injected into the passage of the recirculation exhaust gas nozzle and the passage of the secondary air nozzle.
　従って、流体燃料を再循環排ガスノズルの通路と２次空気ノズルの通路に噴射することで、一部の流体燃料が再循環排ガスと混合し、残りの流体燃料が２次空気と混合した後、ノズル先端部から噴射されて着火することとなり、十分な着火性を確保しながら、ノズル先端部から火炎を遠ざけることで、ノズル先端部の熱損傷を適正に防止することができる。 Therefore, by injecting the fluid fuel into the passages of the recirculating exhaust gas nozzle and the passage of the secondary air nozzle, a portion of the fluid fuel mixes with the recirculating exhaust gas and the remaining fluid fuel mixes with the secondary air, It will be injected from the nozzle tip and ignited, and heat damage to the nozzle tip can be appropriately prevented by keeping the flame away from the nozzle tip while securing sufficient ignitability.
　本発明の燃焼バーナでは、前記第２燃料ノズルは、前記再循環排ガスノズルの通路に予め設定された燃料量の３０％～４０％の流体燃料を噴射することを特徴としている。 In the combustion burner of the present invention, the second fuel nozzle is characterized in that 30% to 40% of the fluid fuel of a fuel amount preset in the passage of the recirculation exhaust gas nozzle is injected.
　従って、再循環排ガスノズルの通路に噴射する流体燃料と２次空気ノズルの通路に噴射する流体燃料の割合を適正値とすることで、十分な着火性とノズル先端部の熱損傷の防止の両立化を図ることができる。 Therefore, by setting the ratio of the fluid fuel injected into the passage of the recirculating exhaust gas nozzle and the fluid fuel injected into the passage of the secondary air nozzle to an appropriate value, it is possible to achieve both sufficient ignitability and prevention of thermal damage to the nozzle tip. Can be implemented.
　本発明の燃焼バーナでは、前記第２燃料ノズルは、前記再循環排ガスノズルの通路に流体燃料を全量噴射することを特徴としている。 In the combustion burner of the present invention, the second fuel nozzle is characterized in that the entire amount of fluid fuel is injected into the passage of the recirculation exhaust gas nozzle.
　従って、流体燃料の全てを再循環排ガスノズルの通路に噴射することで、ノズル先端部から火炎を遠ざけることで、ノズル先端部の熱損傷を適正に防止することができる。 Therefore, thermal damage to the nozzle tip can be properly prevented by injecting all of the fluid fuel into the passage of the recirculation exhaust gas nozzle, and by keeping the flame away from the nozzle tip.
　また、本発明の燃焼バーナは、空気を噴射する空気ノズルと、前記空気ノズルの外側で流体燃料を噴射する第１燃料ノズルと、前記第１燃料ノズルの外側で１次空気を噴射する１次空気ノズルと、前記１次空気ノズルの外側で２次空気を噴射する２次空気ノズルと、前記２次空気ノズルの通路に流体燃料を噴射する第２燃料ノズルと、前記２次空気ノズルの通路に再循環排ガスを噴出する再循環排ガスノズルと、を有することを特徴とするものである。 In the combustion burner according to the present invention, an air nozzle for injecting air, a first fuel nozzle for injecting fluid fuel outside the air nozzle, and a primary for injecting primary air outside the first fuel nozzle An air nozzle, a secondary air nozzle for injecting secondary air outside the primary air nozzle, a second fuel nozzle for injecting fluid fuel into the passage of the secondary air nozzle, and a passage for the secondary air nozzle And a recirculated exhaust gas nozzle for spouting the recirculated exhaust gas.
　従って、第１燃料ノズルから噴射された流体燃料は、空気ノズルから噴射された空気と混合すると共に１次空気ノズルから噴射された１次空気と混合し、着火することで拡散火炎を形成する。また、第２燃料ノズルから噴射された流体燃料は、２次空気ノズルの通路で２次空気及び再循環排ガスと混合した後に噴射され、着火することで予混合火炎を形成する。そのため、流体燃料と空気の混合比を適正比にすることでＮＯｘ発生量を低減することができる。また、このとき、第２燃料ノズルから噴射された燃料は、２次空気及び再循環排ガスと混合した後に着火することで、予混合火炎がノズル先端部から離間した領域で緩慢燃焼することとなり、ノズル先端部の熱損傷を防止することができる。 Therefore, the fluid fuel injected from the first fuel nozzle mixes with the air injected from the air nozzle, mixes with the primary air injected from the primary air nozzle, and forms a diffusion flame by igniting. Further, the fluid fuel injected from the second fuel nozzle is mixed with the secondary air and the recirculated exhaust gas in the passage of the secondary air nozzle, and then injected and ignited to form a premixed flame. Therefore, the NOx generation amount can be reduced by setting the mixing ratio of the fluid fuel and air to an appropriate ratio. At this time, the fuel injected from the second fuel nozzle is mixed with the secondary air and the recirculated exhaust gas and ignited, so that the premixed flame slowly burns in a region separated from the nozzle tip, Thermal damage to the nozzle tip can be prevented.
　本発明の燃焼バーナでは、前記再循環排ガスノズルは、前記２次空気ノズルの外側に配置され、２次空気の外側に再循環排ガスを噴出すると共に、前記２次空気ノズルの通路に再循環排ガスを噴出することを特徴としている。 In the combustion burner according to the present invention, the recirculation exhaust gas nozzle is disposed outside the secondary air nozzle and ejects the recirculation exhaust gas to the outside of the secondary air, and the recirculation exhaust gas in the passage of the secondary air nozzle It is characterized by spouting.
　従って、第２燃料ノズルから噴射された流体燃料は、２次空気ノズルの通路で２次空気及び一部の再循環排ガスと混合した後に噴射されることで、一部の再循環排ガスが流体燃料と混合した後、ノズル先端部から噴射されて着火することとなり、十分な着火性を確保しながら、ノズル先端部から火炎を遠ざけることで、ノズル先端部の熱損傷を適正に防止することができる。 Therefore, the fluid fuel injected from the second fuel nozzle is injected after being mixed with the secondary air and a part of the recirculated exhaust gas in the passage of the secondary air nozzle, whereby a part of the recirculated exhaust gas is a fluid fuel After mixing with this, it will be injected from the tip of the nozzle and ignited, and heat damage to the tip of the nozzle can be properly prevented by keeping the flame away from the tip of the nozzle while securing sufficient ignitability. .
　また、本発明のボイラは、中空形状をなす火炉内で流体燃料と空気を燃焼させると共に、前記火炉内で熱交換を行って熱を回収するボイラにおいて、火炉壁に前記燃焼バーナが配置されることを特徴とするものである。 In the boiler according to the present invention, fluid fuel and air are burned in a hollow furnace and heat exchange is performed in the furnace to recover heat, and the combustion burner is disposed on the furnace wall It is characterized by
　従って、流体燃料と空気の混合比を適正比にすることでＮＯｘ発生量を低減することができると共に、ノズル先端部の熱損傷を防止することができ、その結果、ボイラ効率を向上することができると共に、ボイラの寿命を延長することができる。 Therefore, by setting the mixing ratio of fluid fuel and air to an appropriate ratio, it is possible to reduce the amount of NOx generation and to prevent the thermal damage of the nozzle tip, and as a result, improve the boiler efficiency. As well as being able to extend the life of the boiler.
　本発明の燃焼バーナ及びボイラによれば、第２燃料ノズルから噴射された燃料を事前に再循環排ガスと混合してから噴射するので、流体燃料と空気の混合比を適正比にすることでＮＯｘ発生量を低減することができると共に、ノズル先端部の熱損傷を防止することができる。 According to the combustion burner and the boiler of the present invention, since the fuel injected from the second fuel nozzle is mixed with the recirculated exhaust gas in advance and then injected, NOx can be obtained by making the mixing ratio of the fluid fuel and the air appropriate. The amount of generation can be reduced, and thermal damage to the nozzle tip can be prevented.
図１は、第１実施形態の燃焼バーナを表す断面図である。FIG. 1 is a cross-sectional view showing the combustion burner of the first embodiment. 図２は、燃焼バーナの正面図である。FIG. 2 is a front view of the combustion burner. 図３は、第１実施形態のボイラを表す概略構成図である。FIG. 3 is a schematic configuration diagram showing a boiler of the first embodiment. 図４は、拡散燃焼と予混合燃焼を組み合わせた燃焼バーナの空気比とＮＯｘ発生量との関係を表すグラフである。FIG. 4 is a graph showing the relationship between the air ratio of the combustion burner in which diffusion combustion and premixed combustion are combined and the NOx generation amount. 図５は、第２実施形態の燃焼バーナを表す断面図である。FIG. 5 is a cross-sectional view showing a combustion burner of a second embodiment. 図６は、第３実施形態の燃焼バーナを表す断面図である。FIG. 6 is a cross-sectional view showing a combustion burner of a third embodiment.
　以下に添付図面を参照して、本発明の燃焼バーナ及びボイラの好適な実施形態を詳細に説明する。なお、この実施形態により本発明が限定されるものではなく、また、実施形態が複数ある場合には、各実施形態を組み合わせて構成するものも含むものである。 Hereinafter, preferred embodiments of a combustion burner and a boiler of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited by the embodiments, and in the case where there are a plurality of embodiments, the present invention also includes those configured by combining the respective embodiments.
［第１実施形態］
　図３は、第１実施形態のボイラを表す概略構成図である。 First Embodiment
FIG. 3 is a schematic configuration diagram showing a boiler of the first embodiment.
　第１実施形態のボイラは、流体燃料としてガス燃料（天然ガス）用い、このガス燃料と空気を燃焼バーナにより噴射して火炉内で燃焼させ、この燃焼により発生した熱を回収することが可能なボイラである。また、第１実施形態のボイラは、流体燃料だけでなく、重油（または、軽油、石炭のスラリーなど）を燃料として用い、この重油を燃焼バーナにより噴射して火炉内で燃焼させることもできる。 The boiler of the first embodiment can use gas fuel (natural gas) as fluid fuel, inject this gas fuel and air by a combustion burner, burn it in a furnace, and recover the heat generated by this combustion It is a boiler. Moreover, the boiler of the first embodiment can use not only fluid fuel but also heavy oil (or light oil, slurry of coal, etc.) as fuel, and this heavy oil can be injected by a combustion burner and burned in a furnace.
　第１実施形態において、図３に示すように、ボイラ１０は、コンベンショナルボイラであって、火炉１１と燃焼装置１２とを有している。火炉１１は、四角筒の中空形状をなして鉛直方向に沿って設置され、この火炉１１を構成する火炉壁の下部に燃焼装置１２が設けられている。 In the first embodiment, as shown in FIG. 3, the boiler 10 is a conventional boiler, and includes a furnace 11 and a combustion device 12. The furnace 11 has a hollow shape of a square cylinder and is installed along the vertical direction, and the combustion apparatus 12 is provided at the lower part of the furnace wall constituting the furnace 11.
　燃焼装置１２は、火炉壁に装着された複数の燃焼バーナ２１を有している。本実施形態にて、この燃焼バーナ２１は、周方向に沿って、例えば、４個均等間隔で配設されたものが１セットとして、鉛直方向に沿って、例えば、３セット、つまり、３段配置されている。なお、燃焼バーナ２１の配置場所や個数はこれに限定されるものではない。 The combustion device 12 has a plurality of combustion burners 21 mounted on the furnace wall. In this embodiment, the combustion burners 21 are, for example, four arranged at equal intervals along the circumferential direction, for example, three sets, that is, three stages along the vertical direction. It is arranged. The arrangement location and the number of the combustion burners 21 are not limited to this.
　各燃焼バーナ２１は、燃料供給配管２２を介して燃料供給源２３に連結されており、燃料供給配管２２に燃料供給量を調整可能な流量調整弁２４が設けられている。また、火炉１１は、各燃焼バーナ２１の装着位置に風箱２５が設けられており、この風箱２５に空気ダクト２６の一端部が連結されており、この空気ダクト２６は、他端部に送風機２７が装着されている。 Each combustion burner 21 is connected to a fuel supply source 23 via a fuel supply pipe 22, and the fuel supply pipe 22 is provided with a flow control valve 24 capable of adjusting a fuel supply amount. In the furnace 11, an air box 25 is provided at the mounting position of each combustion burner 21. One end of an air duct 26 is connected to the air box 25. The air duct 26 is connected to the other end. A blower 27 is mounted.
　従って、各燃焼バーナ２１は、燃料供給源２３から燃料供給配管２２を通してガス燃料が供給される。また、各燃焼バーナ２１は、空気ダクト２６から排ガスと熱交換して加熱された燃焼用空気が風箱２５に供給される。そのため、燃焼バーナ２１は、ガス燃料を火炉１１内に噴射すると共に、燃焼用空気を火炉１１内に噴射して着火することで、火炉１１内で火炎を形成することができる。 Therefore, each combustion burner 21 is supplied with gaseous fuel from the fuel supply source 23 through the fuel supply pipe 22. In each of the combustion burners 21, the combustion air heated from the air duct 26 in heat exchange with the exhaust gas is supplied to the air box 25. Therefore, the combustion burner 21 can form a flame in the furnace 11 by injecting gas fuel into the furnace 11 and injecting combustion air into the furnace 11 to ignite the same.
　火炉１１は、上部に煙道３１が連結されており、この煙道３１に、対流伝熱部（熱回収部）として排ガスの熱を回収するための過熱器（スーパーヒータ）３２，３３、再熱器（リヒータ）３４，３５、節炭器（エコノマイザ）３６，３７，３８が設けられており、火炉１１での燃焼で発生した排ガスと水との間で熱交換が行われる。 The flue 31 is connected to the upper part of the furnace 11 and superheaters (super heaters) 32, 33 for recovering the heat of the exhaust gas as a convection heat transfer part (heat recovery part) are connected to the flue 31. Heaters (reheaters) 34, 35 and economizers (economizers) 36, 37, 38 are provided, and heat exchange is performed between the exhaust gas generated by the combustion in the furnace 11 and water.
　煙道３１は、その下流側に熱交換を行った排ガスが排出される排ガス管３９が連結されている。この排ガス管３９は、図示しないが、脱硝装置、電気集塵機、誘引送風機、脱硫装置が設けられ、下流端部に煙突が設けられている。 The flue 31 is connected downstream with an exhaust gas pipe 39 through which the exhaust gas subjected to heat exchange is discharged. Although not shown, the exhaust gas pipe 39 is provided with a NOx removal device, an electrostatic precipitator, an induction fan, and a desulfurization device, and a chimney is provided at the downstream end.
　従って、燃焼装置１２の各燃焼バーナ２１が燃料と蒸気との混合流体を火炉１１内に噴射すると、火炉１１では、混合流体と空気とが燃焼して火炎が生じ、この火炉１１内の下部で火炎が生じると、燃焼ガス（排ガス）がこの火炉１１内を上昇し、煙道３１に排出される。 Therefore, when each combustion burner 21 of the combustion device 12 injects a mixed fluid of fuel and steam into the furnace 11, the mixed fluid and air are burned in the furnace 11 to generate a flame, and the lower part in the furnace 11 When a flame is generated, the combustion gas (exhaust gas) ascends in the furnace 11 and is discharged to the flue 31.
　このとき、図示しない給水ポンプから供給された水は、節炭器３６，３７，３８によって予熱された後、図示しない蒸気ドラムに供給され火炉壁の各水管（図示せず）に供給される間に加熱されて飽和蒸気となり、図示しない蒸気ドラムに送り込まれる。更に、図示しない蒸気ドラムの飽和蒸気は過熱器３２，３３に導入され、燃焼ガスによって過熱される。過熱器３２，３３で生成された過熱蒸気は、図示しない発電プラント（例えば、タービン等）に供給される。また、タービンでの膨張過程の途中で取り出した蒸気は、再熱器３４，３５に導入され、再度過熱されてタービンに戻される。なお、火炉１１をドラム型（蒸気ドラム）として説明したが、この構造に限定されるものではない。 At this time, water supplied from a water supply pump (not shown) is preheated by economizers 36, 37, 38 and then supplied to a steam drum (not shown) and supplied to water pipes (not shown) of the furnace wall. It is heated to become saturated steam and is fed to a steam drum (not shown). Furthermore, saturated steam of a steam drum (not shown) is introduced into the superheaters 32, 33 and is overheated by the combustion gas. The superheated steam generated by the superheaters 32 and 33 is supplied to a power plant (for example, a turbine etc.) not shown. Further, the steam taken out in the middle of the expansion process in the turbine is introduced into the reheaters 34, 35, and is again overheated and returned to the turbine. In addition, although the furnace 11 was demonstrated as a drum type (steam drum), it is not limited to this structure.
　その後、煙道３１の節炭器３６，３７，３８を通過した排ガスは、排ガス管３９にて、図示しない脱硝装置にて、触媒によりＮＯｘなどの有害物質が除去され、電気集塵機で粒子状物質が除去され、脱硫装置により硫黄分が除去された後、煙突から大気中に排出される。 After that, the exhaust gas that has passed through the economizers 36, 37, 38 of the flue 31 is subjected to exhaust gas pipe 39 with a NOx removal device (not shown) to remove harmful substances such as NOx by the catalyst and particulate matter with an electrostatic precipitator Is removed and the sulfur content is removed by the desulfurization device, and then discharged to the atmosphere from the chimney.
　ここで、燃焼バーナ２１について詳細に説明する。図１は、第１実施形態の燃焼バーナを表す断面図、図２は、燃焼バーナの正面図である。 Here, the combustion burner 21 will be described in detail. FIG. 1 is a cross-sectional view showing the combustion burner of the first embodiment, and FIG. 2 is a front view of the combustion burner.
　図１及び図２に示すように、燃焼バーナ２１は、中心（軸心Ｏ）側から外側に向けて配置される空気ノズル４１と、第１燃料ノズル４２と、１次空気ノズル４３と、２次空気ノズル４４と、再循環排ガスノズル４５と、第２燃料ノズル４６とを有している。 As shown in FIGS. 1 and 2, the combustion burner 21 includes an air nozzle 41 disposed from the center (axial center O) side to the outside, a first fuel nozzle 42, and a primary air nozzle 43, 2. A secondary air nozzle 44, a recirculating exhaust gas nozzle 45, and a second fuel nozzle 46 are provided.
　中心軸５１は、円柱形状をなし、この中心軸５１の外周面から外側に所定距離離間して円筒管５２が設けられることで、中心軸５１と円筒管５２の間に空気ノズル４１を構成する通路４１ａが軸方向に沿って形成されている。中心軸５１は、先端部に着火部６１が設けられると共に、外周面にリング形状をなす保炎器６２が通路４１ａ側に突出するように設けられている。円筒管５２は、外周面から外側に所定距離離間して円筒管５３が設けられており、この各円筒管５２，５３の間に周方向に所定間隔で複数（本実施形態では、６個）の第１燃料ノズル４２が配置され、内部に通路４２ａが軸方向に沿って形成されている。 The central axis 51 has a cylindrical shape, and the cylindrical tube 52 is provided at a predetermined distance outside the outer peripheral surface of the central axis 51 to configure the air nozzle 41 between the central axis 51 and the cylindrical tube 52. The passage 41a is formed along the axial direction. The central shaft 51 is provided with an ignition unit 61 at its tip end, and a ring-shaped flame stabilizer 62 is provided on the outer peripheral surface so as to protrude toward the passage 41 a. The cylindrical tubes 52 are provided with a cylindrical tube 53 spaced apart from the outer peripheral surface by a predetermined distance outside, and a plurality (six in this embodiment) of the cylindrical tubes 52 and 53 at predetermined intervals in the circumferential direction. The first fuel nozzle 42 is disposed, and a passage 42a is formed in the inside along the axial direction.
　また、円筒管５３は、外周面から外側に所定距離離間して円筒管５４が設けられることで、各円筒管５３，５４の間に１次空気ノズル４３を構成する通路４３ａが軸方向に沿って形成されている。円筒管５４は、外周面から外側に所定距離離間して円筒管５５が設けられることで、各円筒管５４，５５の間に２次空気ノズル４４を構成する通路４４ａが軸方向に沿って形成されている。円筒管５５は、外周面から外側に所定距離離間して円筒管５６が設けられることで、各円筒管５５，５６の間に再循環排ガスノズル４５を構成する通路４５ａが軸方向に沿って形成されている。 Further, the cylindrical tube 53 is provided with the cylindrical tube 54 at a predetermined distance away from the outer peripheral surface so that the passage 43a constituting the primary air nozzle 43 between the respective cylindrical tubes 53 and 54 extends in the axial direction. It is formed. The cylindrical pipe 54 is provided with a cylindrical pipe 55 spaced apart from the outer peripheral surface by a predetermined distance, so that a passage 44 a constituting the secondary air nozzle 44 is formed along the axial direction between the cylindrical pipes 54 and 55. It is done. The cylindrical pipe 55 is provided with a cylindrical pipe 56 spaced apart from the outer peripheral surface by a predetermined distance so that a passage 45a constituting the recirculation exhaust gas nozzle 45 is formed along the axial direction between the respective cylindrical pipes 55, 56. It is done.
　第２燃料ノズル４６は、円筒管５５，５６の周方向に均等間隔で複数（本実施形態では、４個）設けられている。各第２燃料ノズル４６は、円筒管５６の外側から円筒管５５まで貫通し、通路４５ａに配置されている。 A plurality of (four in the present embodiment) second fuel nozzles 46 are provided at equal intervals in the circumferential direction of the cylindrical tubes 55 and 56. Each second fuel nozzle 46 penetrates from the outside of the cylindrical tube 56 to the cylindrical tube 55, and is disposed in the passage 45a.
　空気ノズル４１は、通路４１ａに空気が供給され、前方に向けてこの空気を噴射することができる。第１燃料ノズル４２は、通路４２ａにガス燃料が供給され、空気ノズル４１の外側で前方に向けてこのガス燃料（ウィーク燃料）を噴射することができる。１次空気ノズル４３は、通路４３ａに１次空気が供給され、第１燃料ノズル４２の外側で前方に向けてこの１次空気を噴射することができる。２次空気ノズル４４は、通路４４ａに２次空気が供給され、１次空気ノズル４３の外側で前方に向けてこの２次空気を噴射することができる。再循環排ガスノズル４５は、通路４５ａに再循環排ガスが供給され、２次空気ノズル４４の外側で前方に向けてこの再循環排ガスを噴射することができる。第２燃料ノズル４６は、再循環排ガスが供給される再循環排ガスノズル４５の通路４５ａにガス燃料（コンク燃料）を噴射することができる。 The air nozzle 41 can supply air to the passage 41a and can jet the air forward. The first fuel nozzle 42 can supply gas fuel to the passage 42 a and inject the gas fuel (weak fuel) forward on the outside of the air nozzle 41. The primary air nozzle 43 can supply the primary air to the passage 43 a and inject the primary air forward on the outside of the first fuel nozzle 42. The secondary air nozzle 44 can supply the secondary air to the passage 44 a and can jet the secondary air forward on the outside of the primary air nozzle 43. The recirculation exhaust gas nozzle 45 can supply the recirculation exhaust gas to the passage 45 a and can jet the recirculation exhaust gas forward on the outside of the secondary air nozzle 44. The second fuel nozzle 46 can inject gas fuel (conch fuel) into the passage 45 a of the recirculation exhaust gas nozzle 45 to which the recirculation exhaust gas is supplied.
　この第１実施形態にて、第２燃料ノズル４６は、再循環排ガスノズル４５の通路４５ａにガス燃料を全量噴射するようにしている。 In the first embodiment, the second fuel nozzle 46 injects the entire amount of gas fuel into the passage 45 a of the recirculation exhaust gas nozzle 45.
　ここで、第１実施形態の燃焼バーナ２１の作用について説明する。以下の説明では、空気は白吹きの矢印で表し、燃料は斜線の矢印で表し、再循環排ガスは点入りの矢印で表す。 Here, the operation of the combustion burner 21 of the first embodiment will be described. In the following description, air is represented by a white-blown arrow, fuel is represented by a hatched arrow, and recirculated exhaust gas is represented by a dotted arrow.
　空気ノズル４１が前方に向けて空気を噴射し、第１燃料ノズル４２が前方に向けてガス燃料を噴射する。すると、空気が保炎器６２により中心（軸心Ｏ）側への旋回流となることから、ガス燃料もこの旋回流により中心（軸心Ｏ）側に巻き込まれる。そのため、ガス燃料と空気が混合し、着火部６１により着火されて拡散火炎（燃料過濃火炎）Ａが形成される。そして、１次空気ノズル４３が前方に向けて１次空気を噴射し、２次空気ノズル４４が前方に向けて２次空気を噴射する。また、再循環排ガスノズル４５が前方に向けて再循環排ガスを噴射し、第２燃料ノズル４６が再循環排ガスノズル４５の通路４５ａにガス燃料を噴射する。そのため、前方に噴射された２次空気とガス燃料が混合した再循環排ガスとがノズル４４，４５の前方で混合し、拡散火炎Ａが火種として着火されて予混合火炎（燃料希薄火炎）Ｂが形成される。 The air nozzle 41 jets air forward, and the first fuel nozzle 42 jets gas fuel forward. Then, since the air becomes a swirling flow toward the center (axial center O) by the flame holder 62, the gas fuel is also attracted to the central (axial center O) side by the swirling flow. Therefore, the gas fuel and the air are mixed and ignited by the igniter 61 to form a diffusion flame (fuel rich flame) A. Then, the primary air nozzle 43 jets the primary air toward the front, and the secondary air nozzle 44 jets the secondary air toward the front. Further, the recirculation exhaust gas nozzle 45 injects the recirculation exhaust gas forward, and the second fuel nozzle 46 injects the gas fuel into the passage 45 a of the recirculation exhaust gas nozzle 45. Therefore, the recirculation exhaust gas in which the secondary air injected to the front and the gas fuel are mixed is mixed in front of the nozzles 44 and 45, and the diffusion flame A is ignited as a spark and a premixed flame (fuel lean flame) B is It is formed.
　このとき、ガス燃料が再循環排ガスノズル４５の通路４５ａに噴射される。再循環排ガスは、ガス燃料と空気が燃焼して発生したものであり、空気がほとんど含まれておらず、ガス燃料と混合しても着火しにくい。そのため、再循環排ガスノズル４５からガス燃料が含有された再循環排ガスが噴射され、第２燃料ノズル４６から２次空気が噴射されると、ガス燃料が含有された再循環排ガスと２次空気との混合気は着火しにくく、予混合火炎Ｂは、ノズル４４，４５の先端部から所定距離だけ離間した前方の領域で形成される。従って、予混合火炎Ｂがノズル４４，４５の先端部に近づくことはなく、このノズル４４，４５の先端部が熱損傷することはない。 At this time, gas fuel is injected into the passage 45 a of the recirculation exhaust gas nozzle 45. The recirculated exhaust gas is generated by combustion of gas fuel and air, contains almost no air, and is difficult to ignite even when mixed with gas fuel. Therefore, when the recirculation exhaust gas containing the gas fuel is injected from the recirculation exhaust gas nozzle 45 and the secondary air is injected from the second fuel nozzle 46, the recirculation exhaust gas containing the gas fuel and the secondary air The air-fuel mixture is difficult to ignite, and the premixed flame B is formed in a front region spaced apart from the tip of the nozzles 44 and 45 by a predetermined distance. Therefore, the premixed flame B does not approach the tips of the nozzles 44 and 45, and the tips of the nozzles 44 and 45 are not thermally damaged.
　ところで、第１実施形態の燃焼バーナ２１は、予混合燃焼と拡散燃焼とを組み合わせたものである。図４は、拡散燃焼と予混合燃焼を組み合わせた燃焼バーナの空気比とＮＯｘ発生量との関係を表すグラフである。 The combustion burner 21 of the first embodiment is a combination of premixed combustion and diffusion combustion. FIG. 4 is a graph showing the relationship between the air ratio of the combustion burner in which diffusion combustion and premixed combustion are combined and the NOx generation amount.
　図４に示すように、ガス燃料が燃焼したときに発生するＮＯｘの濃度は、空気と燃料との比（空気比）により変化する。この場合、予混合燃焼と拡散燃焼とでは、空気比（空気／燃料）に応じて発生するＮＯｘの濃度が変化する。予混合燃焼（予混合火炎Ｂ）にて、ＮＯｘの濃度は、空気比が高い（空気が多い）領域または空気比が低い（空気が少ない）領域で低く、空気比が１．０（理論空気比）近傍で高い。一方、拡散燃焼（拡散火炎Ａ）にて、ＮＯｘの濃度は、空気比が低い（空気が少ない）領域で低く、空気比が高い（空気が多い）領域で低い。そのため、第１実施形態の燃焼バーナ２１は、予混合燃焼にて、空気比が高くてＮＯｘの濃度が低い位置ｂと、拡散燃焼にて、空気比が低くてＮＯｘの濃度が低い位置ａを結んだ点線を用い、全体として、空気比が１．０（理論空気比）より高い位置ｃを基準とし、予混合燃焼と拡散燃焼を分けて燃焼させることで、燃焼バーナ全体としてのＮＯｘ発生量を低減させることができる。 As shown in FIG. 4, the concentration of NOx generated when the gas fuel burns varies with the ratio of air to fuel (air ratio). In this case, the concentration of NOx generated changes depending on the air ratio (air / fuel) between the premixed combustion and the diffusion combustion. In premixed combustion (premixed flame B), the concentration of NOx is low in the high air ratio (more air) region or the low air ratio (less air) region, the air ratio is 1.0 (theoretical air) Ratio) is high. On the other hand, in the diffusion combustion (diffusion flame A), the concentration of NOx is low in the region where the air ratio is low (less air) and is low in the region where the air ratio is high (more air). Therefore, in the combustion burner 21 of the first embodiment, the position b where the air ratio is high and the concentration of NOx is low in premixed combustion, and the position a where the air ratio is low and concentration of NOx is low in diffusion combustion By using the dotted line connected as a whole, and based on the position c where the air ratio is higher than 1.0 (theoretical air ratio), by separately performing premixed combustion and diffusion combustion, the amount of NOx generated as the entire combustion burner Can be reduced.
　このように第１実施形態の燃焼バーナにあっては、空気を噴射する空気ノズル４１と、空気ノズル４１の外側でガス燃料を噴射する第１燃料ノズル４２と、第１燃料ノズル４２の外側で１次空気を噴射する１次空気ノズル４３と、１次空気ノズル４３の外側で２次空気を噴射する２次空気ノズル４４と、２次空気ノズル４４の外側で再循環排ガスを噴出する再循環排ガスノズル４５と、再循環排ガスノズル４５の通路４５ａにガス燃料を噴射する第２燃料ノズル４６とを設けている。 As described above, in the combustion burner of the first embodiment, the air nozzle 41 for injecting air, the first fuel nozzle 42 for injecting gas fuel outside the air nozzle 41, and the outside of the first fuel nozzle 42 A primary air nozzle 43 that jets primary air, a secondary air nozzle 44 that jets secondary air outside the primary air nozzle 43, and a recirculation that jets recirculated exhaust gas outside the secondary air nozzle 44 An exhaust gas nozzle 45 and a second fuel nozzle 46 for injecting gas fuel into the passage 45 a of the recirculation exhaust gas nozzle 45 are provided.
　従って、第１燃料ノズル４２から噴射されたガス燃料は、空気ノズル４１から噴射された空気と混合すると共に１次空気ノズル４３から噴射された１次空気と混合し、着火することで拡散火炎Ａを形成する。また、第２燃料ノズル４６から噴射されたガス燃料は、再循環排ガスノズル４５内の再循環排ガスと混合した後に噴射され、２次空気ノズル４４から噴射された２次空気と混合し、着火することで予混合火炎Ｂを形成する。そのため、ガス燃料と空気との混合比を適正比にすることでＮＯｘ発生量を低減することができる。また、このとき、第２燃料ノズル４６から噴射されたガス燃料は、再循環排ガスと混合した後に２次空気と混合して着火することで、予混合火炎Ｂがノズル先端部から離間した領域で緩慢燃焼することとなり、ノズル先端部の熱損傷を防止することができる。 Therefore, the gaseous fuel injected from the first fuel nozzle 42 mixes with the air injected from the air nozzle 41 and mixes with the primary air injected from the primary air nozzle 43, and is ignited by igniting it. Form Further, the gas fuel injected from the second fuel nozzle 46 is injected after being mixed with the recirculated exhaust gas in the recirculated exhaust gas nozzle 45, mixed with the secondary air injected from the secondary air nozzle 44, and ignited Form a premixed flame B. Therefore, the NOx generation amount can be reduced by setting the mixing ratio of the gas fuel to the air to an appropriate ratio. Further, at this time, the gaseous fuel injected from the second fuel nozzle 46 is mixed with the recirculated exhaust gas, mixed with the secondary air, and ignited, in a region where the premixed flame B is separated from the nozzle tip. It will burn slowly and can prevent the heat damage of the nozzle tip.
　第１実施形態の燃焼バーナでは、第２燃料ノズル４６は、再循環排ガスノズル４５の通路４５ａにガス燃料を全量噴射している。従って、ガス燃料の全てを再循環排ガスノズル４５の通路４５ａに噴射することで、ノズル先端部から火炎を遠ざけることで、ノズル先端部の熱損傷を適正に防止することができる。 In the combustion burner of the first embodiment, the second fuel nozzle 46 injects the entire amount of gas fuel into the passage 45 a of the recirculation exhaust gas nozzle 45. Therefore, by injecting all of the gas fuel into the passage 45a of the recirculation exhaust gas nozzle 45, heat damage to the nozzle tip can be properly prevented by keeping the flame away from the nozzle tip.
　また、第１実施形態のボイラにあっては、中空形状をなす火炉１１内でガス燃料と空気を燃焼させると共に、火炉１１内で熱交換を行って熱を回収するボイラにおいて、火炉壁に燃焼バーナ２１を配置している。従って、燃焼バーナ２１にて、ガス燃料と空気の混合比を適正比にすることでＮＯｘ発生量を低減することができると共に、ノズル先端部の熱損傷を防止することができ、その結果、ボイラ効率を向上することができると共に、ボイラの寿命を延長することができる。 In the boiler according to the first embodiment, the gas fuel and the air are burned in the hollow furnace 11 and heat exchange is performed in the furnace 11 to recover the heat. A burner 21 is disposed. Therefore, by setting the mixing ratio of gas fuel to air to an appropriate ratio in the combustion burner 21, it is possible to reduce the amount of NOx generation and to prevent the thermal damage of the nozzle tip, and as a result, the boiler The efficiency can be improved and the life of the boiler can be extended.
［第２実施形態］
　図５は、第２実施形態の燃焼バーナを表す断面図である。なお、上述した実施形態と同様の機能を有する部材には、同一の符号を付して詳細な説明は省略する。 Second Embodiment
FIG. 5 is a cross-sectional view showing a combustion burner of a second embodiment. The members having the same functions as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.
　第２実施形態において、図５に示すように、燃焼バーナ７１は、中心（軸心Ｏ）側から外側に向けて配置される空気ノズル４１と、第１燃料ノズル４２と、１次空気ノズル４３と、２次空気ノズル４４と、再循環排ガスノズル４５と、第２燃料ノズル７２とを有している。 In the second embodiment, as shown in FIG. 5, the combustion burner 71 is an air nozzle 41 disposed outward from the center (axial center O) side, a first fuel nozzle 42, and a primary air nozzle 43. , A secondary air nozzle 44, a recirculation exhaust gas nozzle 45, and a second fuel nozzle 72.
　第２燃料ノズル７２は、円筒管５４，５５，５６の周方向に均等間隔で複数設けられている。各第２燃料ノズル７２は、円筒管５６の外側から円筒管５４まで貫通し、通路４４ａ，４５ａに配置されている。 A plurality of second fuel nozzles 72 are provided at equal intervals in the circumferential direction of the cylindrical tubes 54, 55, 56. Each second fuel nozzle 72 penetrates from the outside of the cylindrical tube 56 to the cylindrical tube 54, and is disposed in the passages 44a and 45a.
　空気ノズル４１は、通路４１ａに空気が供給され、前方に向けてこの空気を噴射することができる。第１燃料ノズル４２は、通路４２ａにガス燃料が供給され、空気ノズル４１の外側で前方に向けてこのガス燃料（ウィーク燃料）を噴射することができる。１次空気ノズル４３は、通路４３ａに１次空気が供給され、第１燃料ノズル４２の外側で前方に向けてこの１次空気を噴射することができる。２次空気ノズル４４は、通路４４ａに２次空気が供給され、１次空気ノズル４３の外側で前方に向けてこの２次空気を噴射することができる。再循環排ガスノズル４５は、通路４５ａに再循環排ガスが供給され、２次空気ノズル４４の外側で前方に向けてこの再循環排ガスを噴射することができる。第２燃料ノズル７２は、２次空気が供給される２次空気ノズル４４の通路４４ａと、再循環排ガスが供給される再循環排ガスノズル４５の通路４５ａの両方にガス燃料（コンク燃料）を噴射することができる。 The air nozzle 41 can supply air to the passage 41a and can jet the air forward. The first fuel nozzle 42 can supply gas fuel to the passage 42 a and inject the gas fuel (weak fuel) forward on the outside of the air nozzle 41. The primary air nozzle 43 can supply the primary air to the passage 43 a and inject the primary air forward on the outside of the first fuel nozzle 42. The secondary air nozzle 44 can supply the secondary air to the passage 44 a and can jet the secondary air forward on the outside of the primary air nozzle 43. The recirculation exhaust gas nozzle 45 can supply the recirculation exhaust gas to the passage 45 a and can jet the recirculation exhaust gas forward on the outside of the secondary air nozzle 44. The second fuel nozzle 72 injects the gas fuel (conch fuel) into both the passage 44a of the secondary air nozzle 44 to which the secondary air is supplied and the passage 45a of the recirculation exhaust gas nozzle 45 to which the recirculated exhaust gas is supplied. can do.
　この第２実施形態にて、第２燃料ノズル７２は、再循環排ガスノズル４５の通路４５ａに予め設定された燃料量の３０％～４０％のガス燃料を噴射するようにしている。即ち、第２燃料ノズル７２が噴射するガス燃料の３０％～４０％のガス燃料を再循環排ガスノズル４５の通路４５ａに噴射し、残りの６０％～７０％のガス燃料を２次空気ノズル４４の通路４４ａに噴射する。 In the second embodiment, the second fuel nozzle 72 injects 30% to 40% of gaseous fuel into the passage 45a of the recirculation exhaust gas nozzle 45 in advance. That is, 30% to 40% of the gas fuel injected by the second fuel nozzle 72 is injected into the passage 45a of the recirculation exhaust gas nozzle 45, and the remaining 60% to 70% of the gas fuel is injected into the secondary air nozzle 44. To the passage 44a of the
　空気ノズル４１が前方に向けて空気を噴射し、第１燃料ノズル４２が前方に向けてガス燃料を噴射する。すると、空気が保炎器６２により中心（軸心Ｏ）側への旋回流となることから、ガス燃料もこの旋回流により中心（軸心Ｏ）側に巻き込まれる。そのため、ガス燃料と空気が混合し、着火部６１により着火されて拡散火炎（燃料過濃火炎）Ａが形成される。そして、１次空気ノズル４３が前方に向けて１次空気を噴射し、２次空気ノズル４４が前方に向けて２次空気を噴射し、再循環排ガスノズル４５が前方に向けて再循環排ガスを噴射する。そして、第２燃料ノズル７２が２次空気ノズル４４の通路４４ａと再循環排ガスノズル４５の通路４５ａにガス燃料を噴射する。そのため、２次空気ノズル４４の通路４４ａでガス燃料と２次空気が混合し、更に、前方で再循環排ガス中のガス燃料が混合し、拡散火炎Ａが火種として着火されて予混合火炎（燃料希薄火炎）Ｂが形成される。 The air nozzle 41 jets air forward, and the first fuel nozzle 42 jets gas fuel forward. Then, since the air becomes a swirling flow toward the center (axial center O) by the flame holder 62, the gas fuel is also attracted to the central (axial center O) side by the swirling flow. Therefore, the gas fuel and the air are mixed and ignited by the igniter 61 to form a diffusion flame (fuel rich flame) A. Then, the primary air nozzle 43 jets the primary air forward, the secondary air nozzle 44 jets the secondary air forward, and the recirculation exhaust gas nozzle 45 directs the recirculation exhaust gas Inject. Then, the second fuel nozzle 72 injects the gas fuel into the passage 44 a of the secondary air nozzle 44 and the passage 45 a of the recirculation exhaust gas nozzle 45. Therefore, the gas fuel and the secondary air are mixed in the passage 44a of the secondary air nozzle 44, and further, the gas fuel in the recirculated exhaust gas is mixed in the front, and the diffusion flame A is ignited as a spark to mix the premixed flame (fuel Lean flame) B is formed.
　このとき、ガス燃料が２次空気ノズル４４の通路４４ａと再循環排ガスノズル４５の通路４５ａに噴射される。再循環排ガスは、ガス燃料と空気が燃焼して発生したものであり、空気がほとんど含まれておらず、ガス燃料と混合しても着火しにくい。そのため、再循環排ガスノズル４５からガス燃料が含有された再循環排ガスが噴射され、第２燃料ノズル７２から２次空気とガス燃料の混合気が噴射されると、ガス燃料が含有された再循環排ガスと混合気は着火しにくく、予混合火炎Ｂは、ノズル４４，４５の先端部から所定距離だけ離間した前方の領域で形成される。従って、予混合火炎Ｂがノズル４４，４５の先端部に近づくことはなく、このノズル４４，４５の先端部が熱損傷することはない。 At this time, gaseous fuel is injected into the passage 44 a of the secondary air nozzle 44 and the passage 45 a of the recirculation exhaust gas nozzle 45. The recirculated exhaust gas is generated by combustion of gas fuel and air, contains almost no air, and is difficult to ignite even when mixed with gas fuel. Therefore, when the recirculation exhaust gas containing the gas fuel is injected from the recirculation exhaust gas nozzle 45 and the mixture of the secondary air and the gas fuel is injected from the second fuel nozzle 72, the recirculation containing the gas fuel is performed. The exhaust gas and the air-fuel mixture are not easily ignited, and the premixed flame B is formed in a front region separated from the tip of the nozzles 44 and 45 by a predetermined distance. Therefore, the premixed flame B does not approach the tips of the nozzles 44 and 45, and the tips of the nozzles 44 and 45 are not thermally damaged.
　このように第２実施形態の燃焼バーナにあっては、２次空気ノズル４４の通路４４ａと再循環排ガスノズル４５の通路４５ａにガス燃料を噴射する第２燃料ノズル７２を設けている。 As described above, in the combustion burner of the second embodiment, the second fuel nozzle 72 for injecting the gas fuel is provided in the passage 44 a of the secondary air nozzle 44 and the passage 45 a of the recirculation exhaust gas nozzle 45.
　従って、ガス燃料を２次空気ノズル４４の通路４４ａと再循環排ガスノズル４５の通路４５ａに噴射することで、一部のガス燃料が再循環排ガスと混合し、残りのガス燃料が２次空気と混合した後、ノズル先端部から噴射されて着火することとなり、十分な着火性を確保しながら、ノズル先端部から火炎を遠ざけることで、ノズル先端部の熱損傷を適正に防止することができる。 Therefore, by injecting the gas fuel into the passage 44a of the secondary air nozzle 44 and the passage 45a of the recirculation exhaust gas nozzle 45, a part of the gas fuel is mixed with the recirculation exhaust gas, and the remaining gas fuel is mixed with the secondary air. After mixing, the nozzle tip is injected and ignited, and heat damage to the nozzle tip can be properly prevented by keeping the flame away from the nozzle tip while securing sufficient ignition performance.
　第２実施形態の燃焼バーナでは、第２燃料ノズル７２は、再循環排ガスノズル４５の通路４５ａに予め設定された燃料量の３０％～４０％のガス燃料を噴射する。従って、再循環排ガスノズル４５の通路４５ａに噴射するガス燃料と２次空気ノズル４４の通路４４ａに噴射するガス燃料の割合を適正値とすることで、十分な着火性とノズル先端部の熱損傷の防止の両立化を図ることができる。 In the combustion burner of the second embodiment, the second fuel nozzle 72 injects 30% to 40% of gaseous fuel to the passage 45 a of the recirculating exhaust gas nozzle 45 in advance. Therefore, by setting the ratio of the gas fuel injected into the passage 45a of the recirculating exhaust gas nozzle 45 to the gas fuel injected into the passage 44a of the secondary air nozzle 44 to an appropriate value, sufficient ignitability and thermal damage to the nozzle tip Can be achieved at the same time.
［第３実施形態］
　図６は、第３実施形態の燃焼バーナを表す断面図である。なお、上述した実施形態と同様の機能を有する部材には、同一の符号を付して詳細な説明は省略する。 Third Embodiment
FIG. 6 is a cross-sectional view showing a combustion burner of a third embodiment. The members having the same functions as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.
　第３実施形態において、図６に示すように、燃焼バーナ８１は、中心（軸心Ｏ）側から外側に向けて配置される空気ノズル４１と、第１燃料ノズル４２と、１次空気ノズル４３と、２次空気ノズル４４と、再循環排ガスノズル４５と、第２燃料ノズル８２とを有している。 In the third embodiment, as shown in FIG. 6, the combustion burner 81 has an air nozzle 41, a first fuel nozzle 42, and a primary air nozzle 43 disposed outward from the center (axial center O) side. , A secondary air nozzle 44, a recirculation exhaust gas nozzle 45, and a second fuel nozzle 82.
　円筒管５４は、外周面から外側に所定距離離間して円筒管５５が設けられることで、各円筒管５４，５５の間に２次空気ノズル４４を構成する通路４４ａが軸方向に沿って形成されている。円筒管５５は、外周面から外側に所定距離離間して円筒管５６が設けられることで、各円筒管５５，５６の間に再循環排ガスノズル４５を構成する通路４５ａが軸方向に沿って形成されている。また、円筒管４４は、通路４４ａ，４５ａを連通する開口部８３が形成されている。この開口部８３は、周方向に連続していてもよいし、周方向に所定間隔を空けて複数設けてもよい。更に、開口部８３に代えて通路４４ａ，４５ａを連通する通路を設けてもよい。 The cylindrical pipe 54 is provided with a cylindrical pipe 55 spaced apart from the outer peripheral surface by a predetermined distance, so that a passage 44 a constituting the secondary air nozzle 44 is formed along the axial direction between the cylindrical pipes 54 and 55. It is done. The cylindrical pipe 55 is provided with a cylindrical pipe 56 spaced apart from the outer peripheral surface by a predetermined distance so that a passage 45a constituting the recirculation exhaust gas nozzle 45 is formed along the axial direction between the respective cylindrical pipes 55, 56. It is done. Further, the cylindrical tube 44 is formed with an opening 83 communicating the passages 44a and 45a. The openings 83 may be continuous in the circumferential direction, or a plurality of the openings 83 may be provided at predetermined intervals in the circumferential direction. Furthermore, instead of the opening 83, a passage may be provided to connect the passages 44a and 45a.
　第２燃料ノズル８２は、円筒管５４，５５の周方向に均等間隔で複数設けられている。各第２燃料ノズル８２は、円筒管５５の外側から円筒管５４まで貫通し、通路４４ａに配置されている。 A plurality of second fuel nozzles 82 are provided at equal intervals in the circumferential direction of the cylindrical tubes 54 and 55. Each second fuel nozzle 82 penetrates from the outside of the cylindrical tube 55 to the cylindrical tube 54 and is disposed in the passage 44 a.
　空気ノズル４１は、通路４１ａに空気が供給され、前方に向けてこの空気を噴射することができる。第１燃料ノズル４２は、通路４２ａにガス燃料が供給され、空気ノズル４１の外側で前方に向けてこのガス燃料（ウィーク燃料）を噴射することができる。１次空気ノズル４３は、通路４３ａに１次空気が供給され、第１燃料ノズル４２の外側で前方に向けてこの１次空気を噴射することができる。２次空気ノズル４４は、通路４４ａに２次空気が供給され、１次空気ノズル４３の外側で前方に向けてこの２次空気を噴射することができる。再循環排ガスノズル４５は、通路４５ａに再循環排ガスが供給され、２次空気ノズル４４の外側で前方に向けてこの再循環排ガスを噴射すると共に、一部を２次空気ノズル４４の通路４４ａに噴射することができる。第２燃料ノズル８２は、２次空気と再循環排ガスが供給される２次空気ノズル４４の通路４４ａにガス燃料（コンク燃料）を噴射することができる。 The air nozzle 41 can supply air to the passage 41a and can jet the air forward. The first fuel nozzle 42 can supply gas fuel to the passage 42 a and inject the gas fuel (weak fuel) forward on the outside of the air nozzle 41. The primary air nozzle 43 can supply the primary air to the passage 43 a and inject the primary air forward on the outside of the first fuel nozzle 42. The secondary air nozzle 44 can supply the secondary air to the passage 44 a and can jet the secondary air forward on the outside of the primary air nozzle 43. The recirculation exhaust gas nozzle 45 supplies recirculation exhaust gas to the passage 45 a and injects the recirculation exhaust gas forward toward the outside of the secondary air nozzle 44, and part of the recirculation exhaust gas nozzle 45 in the passage 44 a of the secondary air nozzle 44. It can be injected. The second fuel nozzle 82 can inject gas fuel (conch fuel) into the passage 44 a of the secondary air nozzle 44 to which the secondary air and the recirculated exhaust gas are supplied.
　空気ノズル４１が前方に向けて空気を噴射し、第１燃料ノズル４２が前方に向けてガス燃料を噴射する。すると、空気が保炎器６２により中心（軸心Ｏ）側への旋回流となることから、ガス燃料もこの旋回流により中心（軸心Ｏ）側に巻き込まれる。そのため、ガス燃料と空気が混合し、着火部６１により着火されて拡散火炎（燃料過濃火炎）Ａが形成される。そして、１次空気ノズル４３が前方に向けて１次空気を噴射し、２次空気ノズル４４が前方に向けて２次空気を噴射する。また、再循環排ガスノズル４５が前方に向けて再循環排ガスを噴射すると共に、一部の再循環排ガスを２次空気ノズル４４の通路４４ａに噴射する。そして、第２燃料ノズル８２が２次空気ノズル４４の通路４４ａにガス燃料を噴射する。そのため、前方に噴射された２次空気とガス燃料とがノズル４４，４５の前方で混合し、拡散火炎Ａが火種として着火されて予混合火炎（燃料希薄火炎）Ｂが形成される。 The air nozzle 41 jets air forward, and the first fuel nozzle 42 jets gas fuel forward. Then, since the air becomes a swirling flow toward the center (axial center O) by the flame holder 62, the gas fuel is also attracted to the central (axial center O) side by the swirling flow. Therefore, the gas fuel and the air are mixed and ignited by the igniter 61 to form a diffusion flame (fuel rich flame) A. Then, the primary air nozzle 43 jets the primary air toward the front, and the secondary air nozzle 44 jets the secondary air toward the front. Further, the recirculation exhaust gas nozzle 45 jets the recirculation exhaust gas forward, and injects part of the recirculation exhaust gas into the passage 44 a of the secondary air nozzle 44. Then, the second fuel nozzle 82 injects the gas fuel into the passage 44 a of the secondary air nozzle 44. Therefore, the secondary air and the gas fuel injected forward are mixed in front of the nozzles 44 and 45, and the diffusion flame A is ignited as a flame to form a premixed flame (fuel lean flame) B.
　このとき、再循環排ガスが事前に２次空気ノズル４４の通路４４ａに噴射される。再循環排ガスは、ガス燃料と空気が燃焼して発生したものであり、空気がほとんど含まれておらず、ガス燃料と混合しても着火しにくい。そのため、再循環排ガスを含んだ２次空気にガス燃料が噴射され、第２燃料ノズル８２から２次空気と再循環排ガスとガス燃料が噴射されると、再循環排ガスによりガス燃料と２次空気との混合気は着火しにくく、予混合火炎Ｂは、ノズル４４，４５の先端部から所定距離だけ離間した前方の領域で形成される。従って、予混合火炎Ｂがノズル４４，４５の先端部に近づくことはなく、このノズル４４，４５の先端部が熱損傷することはない。 At this time, the recirculated exhaust gas is injected in advance into the passage 44 a of the secondary air nozzle 44. The recirculated exhaust gas is generated by combustion of gas fuel and air, contains almost no air, and is difficult to ignite even when mixed with gas fuel. Therefore, when the gas fuel is injected to the secondary air containing the recirculation exhaust gas and the secondary air and the recirculation exhaust gas and the gas fuel are injected from the second fuel nozzle 82, the gas fuel and the secondary air are injected by the recirculation exhaust gas. And the premixed flame B is formed in a front region separated from the tip of the nozzles 44 and 45 by a predetermined distance. Therefore, the premixed flame B does not approach the tips of the nozzles 44 and 45, and the tips of the nozzles 44 and 45 are not thermally damaged.
　このように第３実施形態の燃焼バーナにあっては、空気を噴射する空気ノズル４１と、空気ノズル４１の外側でガス燃料を噴射する第１燃料ノズル４２と、第１燃料ノズル４２の外側で１次空気を噴射する１次空気ノズル４３と、１次空気ノズル４３の外側で２次空気を噴射する２次空気ノズル４４と、２次空気ノズル４４の外側で再循環排ガスを噴出すると共に一部を２次空気ノズル４４の通路４４ａに噴射する再循環排ガスノズル４５と、２次空気ノズル４４の通路４４ａにガス燃料を噴射する第２燃料ノズル８２とを設けている。 As described above, in the combustion burner of the third embodiment, the air nozzle 41 for injecting air, the first fuel nozzle 42 for injecting gas fuel outside the air nozzle 41, and the outside of the first fuel nozzle 42 The primary air nozzle 43 injecting primary air, the secondary air nozzle 44 injecting secondary air outside the primary air nozzle 43, and the recirculation exhaust gas outside the secondary air nozzle 44 The recirculation exhaust gas nozzle 45 injects the fuel gas into the passage 44 a of the secondary air nozzle 44, and the second fuel nozzle 82 injects the gas fuel into the passage 44 a of the secondary air nozzle 44.
　従って、第１燃料ノズル４２から噴射されたガス燃料は、空気ノズル４１から噴射された空気と混合すると共に１次空気ノズル４３から噴射された１次空気と混合し、着火することで拡散火炎Ａを形成する。また、第２燃料ノズル８２から噴射されたガス燃料は、２次空気ノズル４４の通路４４ａで２次空気と再循環排ガスとの混合気に対して噴射され、この２次空気と混合し、着火することで予混合火炎Ｂを形成する。そのため、ガス燃料と空気との混合比を適正比にすることでＮＯｘ発生量を低減することができる。また、このとき、第２燃料ノズル８２から噴射されたガス燃料は、２次空気及び再循環排ガスと混合した後に着火することで、予混合火炎Ｂがノズル先端部から離間した領域で緩慢燃焼することとなり、ノズル先端部の熱損傷を防止することができる。 Therefore, the gaseous fuel injected from the first fuel nozzle 42 mixes with the air injected from the air nozzle 41 and mixes with the primary air injected from the primary air nozzle 43, and is ignited by igniting it. Form Further, the gas fuel injected from the second fuel nozzle 82 is injected to the mixture of the secondary air and the recirculated exhaust gas in the passage 44a of the secondary air nozzle 44, mixed with the secondary air, and ignited. Form a premixed flame B. Therefore, the NOx generation amount can be reduced by setting the mixing ratio of the gas fuel to the air to an appropriate ratio. At this time, the gaseous fuel injected from the second fuel nozzle 82 is ignited after being mixed with the secondary air and the recirculated exhaust gas, so that the premixed flame B burns slowly in a region separated from the nozzle tip. As a result, thermal damage to the nozzle tip can be prevented.
　なお、上述した実施形態では、径の異なる複数の円筒管５２，５３，５４，５５，５６を組み合わせることで、空気ノズル４１、第１燃料ノズル４２、１次空気ノズル４３、２次空気ノズル４４、再循環排ガスノズル４５、第２燃料ノズル４６，７２，８２を構成したが、この構成に限定されるものではない。円筒管に代えて四角筒管（多角形筒管）を設けてもよい。また、特許文献２のように、中央部に空気ノズルと第１燃料ノズルを設け、上部及び下部に２次空気ノズルと第２燃料ノズルを設け、その間に１次空気ノズルや再循環排ガスノズルを設けてもよい。 In the embodiment described above, the air nozzle 41, the first fuel nozzle 42, the primary air nozzle 43, and the secondary air nozzle 44 are obtained by combining a plurality of cylindrical tubes 52, 53, 54, 55, and 56 having different diameters. Although the recirculation exhaust gas nozzle 45 and the second fuel nozzles 46, 72, 82 are configured, the present invention is not limited to this configuration. It may replace with a cylindrical pipe and may provide a square cylindrical pipe (polygonal cylindrical pipe). Further, as in Patent Document 2, an air nozzle and a first fuel nozzle are provided at the center, and a secondary air nozzle and a second fuel nozzle are provided at the upper and lower portions, and the primary air nozzle and the recirculation exhaust gas nozzle are interposed therebetween. You may provide.
　また、本発明は、ノズル先端部の前方で着火した予混合火炎がノズル先端部に近づいて熱損傷することを抑制するために、再循環排ガスを有効利用したものであり、第２燃料と２次空気と再循環排ガスの混合順序は上述した実施形態に限定されるものではなく、適宜設定してもよいものである。例えば、第２燃料と２次空気の混合気に再循環排ガスを噴射したりしてもよいものである。 In the present invention, the recirculation exhaust gas is effectively used to prevent the premixed flame ignited in front of the nozzle tip from approaching the nozzle tip and causing thermal damage. The order of mixing the next air and the recirculated exhaust gas is not limited to the embodiment described above, and may be set as appropriate. For example, the recirculation exhaust gas may be injected into the mixture of the second fuel and the secondary air.
　１０　ボイラ
　１１　火炉
　１２　燃焼装置
　２１，７１，８１　燃焼バーナ
　２２　燃料供給配管
　２５　風箱
　２６　空気ダクト
　４１　空気ノズル
　４１ａ，４２ａ，４３ａ，４４ａ，４５ａ　通路
　４２　第１燃料ノズル
　４３　１次空気ノズル
　４４　２次空気ノズル
　４５　再循環排ガスノズル
　４６，７２，８２　第２燃料ノズル
　６１　着火部
　６２　保炎器 DESCRIPTION OF SYMBOLS 10 boiler 11 furnace 12 combustion apparatus 21, 71, 81 combustion burner 22 fuel supply piping 25 air box 26 air duct 41 air nozzle 41a, 42a, 43a, 44a, 45a passage 42 1st fuel nozzle 43 primary air nozzle 44 secondary Air nozzle 45 Recirculation exhaust gas nozzle 46, 72, 82 Second fuel nozzle 61 Ignition part 62 Flame holder

Claims (7)

  1. 　空気を噴射する空気ノズルと、
    　前記空気ノズルの外側で流体燃料を噴射する第１燃料ノズルと、
    　前記第１燃料ノズルの外側で１次空気を噴射する１次空気ノズルと、
    　前記１次空気ノズルの外側で２次空気を噴射する２次空気ノズルと、
    　前記２次空気ノズルの外側で再循環排ガスを噴出する再循環排ガスノズルと、
    　前記再循環排ガスノズルの通路に流体燃料を噴射する第２燃料ノズルと、
    　を有することを特徴とする燃焼バーナ。     An air nozzle for injecting air;
    A first fuel nozzle for injecting fluid fuel outside the air nozzle;
    A primary air nozzle for injecting primary air outside the first fuel nozzle;
    A secondary air nozzle for injecting secondary air outside the primary air nozzle;
    A recirculating exhaust gas nozzle that ejects a recirculating exhaust gas outside the secondary air nozzle;
    A second fuel nozzle for injecting fluid fuel into the passage of the recirculated exhaust gas nozzle;
    A combustion burner characterized by having.
  2. 　前記第２燃料ノズルは、前記再循環排ガスノズルの通路と前記２次空気ノズルの通路に流体燃料を噴射することを特徴とする請求項１に記載の燃焼バーナ。 The combustion burner according to claim 1, wherein the second fuel nozzle injects fluid fuel into the passage of the recirculation exhaust gas nozzle and the passage of the secondary air nozzle.
  3. 　前記第２燃料ノズルは、前記再循環排ガスノズルの通路に予め設定された燃料量の３０％～４０％の流体燃料を噴射することを特徴とする請求項２に記載の燃焼バーナ。 The combustion burner according to claim 2, wherein the second fuel nozzle injects 30% to 40% of a fluid fuel of a preset fuel amount into a passage of the recirculation exhaust gas nozzle.
  4. 　前記第２燃料ノズルは、前記再循環排ガスノズルの通路に流体燃料を全量噴射することを特徴とする請求項１に記載の燃焼バーナ。 The combustion burner according to claim 1, wherein the second fuel nozzle totally injects the fluid fuel into the passage of the recirculation exhaust gas nozzle.
  5. 　空気を噴射する空気ノズルと、
    　前記空気ノズルの外側で流体燃料を噴射する第１燃料ノズルと、
    　前記第１燃料ノズルの外側で１次空気を噴射する１次空気ノズルと、
    　前記１次空気ノズルの外側で２次空気を噴射する２次空気ノズルと、
    　前記２次空気ノズルの通路に流体燃料を噴射する第２燃料ノズルと、
    　前記２次空気ノズルの通路に再循環排ガスを噴出する再循環排ガスノズルと、
    　を有することを特徴とする燃焼バーナ。     An air nozzle for injecting air;
    A first fuel nozzle for injecting fluid fuel outside the air nozzle;
    A primary air nozzle for injecting primary air outside the first fuel nozzle;
    A secondary air nozzle for injecting secondary air outside the primary air nozzle;
    A second fuel nozzle for injecting fluid fuel into the passage of the secondary air nozzle;
    A recirculating exhaust gas nozzle for injecting a recirculating exhaust gas into the passage of the secondary air nozzle;
    A combustion burner characterized by having.
  6. 　前記再循環排ガスノズルは、前記２次空気ノズルの外側に配置され、２次空気の外側に再循環排ガスを噴出すると共に、前記２次空気ノズルの通路に再循環排ガスを噴出することを特徴とする請求項５に記載の燃焼バーナ。 The recirculation exhaust gas nozzle is disposed outside the secondary air nozzle, and ejects recirculation exhaust gas to the outside of the secondary air, and ejects recirculation exhaust gas to the passage of the secondary air nozzle. The combustion burner according to claim 5.
  7. 　中空形状をなす火炉内で流体燃料と空気を燃焼させると共に、前記火炉内で熱交換を行って熱を回収するボイラにおいて、
    　火炉壁に請求項１から請求項６のいずれか一項に記載の燃焼バーナが配置されることを特徴とするボイラ。     A boiler for burning fluid fuel and air in a hollow furnace and performing heat exchange in the furnace to recover heat,
    A boiler characterized in that the combustion burner according to any one of claims 1 to 6 is disposed on a furnace wall.
PCT/JP2015/072618 2014-08-29 2015-08-10 Combustion burner and boiler WO2016031540A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5056228U (en) * 1973-09-21 1975-05-27
JPS5178953U (en) * 1974-12-19 1976-06-22
JPS598009U (en) * 1982-07-08 1984-01-19 バブコツク日立株式会社 combustion device
JPH06123411A (en) * 1992-10-12 1994-05-06 Mitsubishi Heavy Ind Ltd Gas firing burner

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5056228U (en) * 1973-09-21 1975-05-27
JPS5178953U (en) * 1974-12-19 1976-06-22
JPS598009U (en) * 1982-07-08 1984-01-19 バブコツク日立株式会社 combustion device
JPH06123411A (en) * 1992-10-12 1994-05-06 Mitsubishi Heavy Ind Ltd Gas firing burner

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