WO2008056650A1 - Pulverized coal boiler - Google Patents

Pulverized coal boiler Download PDF

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Publication number
WO2008056650A1
WO2008056650A1 PCT/JP2007/071525 JP2007071525W WO2008056650A1 WO 2008056650 A1 WO2008056650 A1 WO 2008056650A1 JP 2007071525 W JP2007071525 W JP 2007071525W WO 2008056650 A1 WO2008056650 A1 WO 2008056650A1
Authority
WO
WIPO (PCT)
Prior art keywords
furnace
pulverized coal
water
steam
fired boiler
Prior art date
Application number
PCT/JP2007/071525
Other languages
French (fr)
Japanese (ja)
Inventor
Akihito Orii
Masayuki Taniguchi
Yuki Kamikawa
Hironobu Kobayashi
Miki Shimogouri
Toshihiko Mine
Shinichiro Nomura
Akira Baba
Yusuke Ochi
Koji Kuramashi
Original Assignee
Babcock-Hitachi K.K.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Babcock-Hitachi K.K. filed Critical Babcock-Hitachi K.K.
Priority to JP2008543076A priority Critical patent/JP5095628B2/en
Priority to EP07831257A priority patent/EP2083216A4/en
Priority to US12/513,959 priority patent/US20100031858A1/en
Publication of WO2008056650A1 publication Critical patent/WO2008056650A1/en

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Classifications

    • 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
    • F23L7/002—Supplying water
    • 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 
    • F23C7/00—Combustion apparatus characterised by arrangements for air supply
    • F23C7/02—Disposition of air supply not passing through burner
    • 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
    • F23L9/00—Passages or apertures for delivering secondary air for completing combustion of fuel 
    • F23L9/02—Passages or apertures for delivering secondary air for completing combustion of fuel  by discharging the air above the fire
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/10—Nitrogen; Compounds thereof
    • F23J2215/101—Nitrous oxide (N2O)
    • 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
    • F23L2900/00—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber
    • F23L2900/07008—Injection of water into the combustion chamber
    • 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
    • F23L2900/00—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber
    • F23L2900/07009—Injection of steam into the combustion chamber

Definitions

  • the present invention relates to a pulverized coal fired boiler that uses pulverized coal as a fuel, and more particularly to a pulverized coal fired boiler that suppresses the generation of thermal nitrogen oxides.
  • a pulverized coal burner is provided in a furnace of a pulverized coal burning boiler, and a after-air port is provided downstream of the burner.
  • the pulverized coal and combustion air are supplied from the PANA, and the combustion air is supplied from the after airport to the pulverized coal fired boiler.
  • the combustion gas combusted by the pulverized coal of fuel flows down in the furnace, and the combustion gas flowing down and the heat exchanger (not shown) installed in the furnace exchange heat to produce the combustion gas.
  • the amount of heat is taken out of the gas, and the low-temperature combustion gas is discharged outside the pulverized coal-fired boiler as furnace power exhaust gas.
  • NOx generated in a boiler is roughly classified into fuel NOx and thermal NOx.
  • F Yuel NOx is generated by the oxidation of nitrogen compounds contained in coal as fuel. This fuel NOx is greatly reduced by improving combustion technology in the PANA!
  • thermal NOx is generated by the oxidation of nitrogen contained in the air at high temperatures.
  • Japanese Patent Laid-Open No. 2003-322310 discloses that for the purpose of reducing this thermal NOx, the combustion temperature is higher than the uppermost burner and below the secondary superheater of the heat exchanger, and the heat load is high. Insert a removable spray nozzle equipped with a drive device from the furnace wall into the center of the furnace and spray water or steam from the spray nozzle onto the center of the furnace to lower the flame temperature of the combustion gas. Techniques for making them disclosed are disclosed.
  • Patent Document 1 Japanese Patent Laid-Open No. 6-201105
  • Patent Document 2 Japanese Patent Laid-Open No. 2003-322310
  • An object of the present invention is to reliably suppress an increase in flame temperature that occurs when unburned gas is burned in the furnace by supplying combustion air from the after-air port, and the concentration of thermal NOx generated during combustion.
  • a pulverized coal burning boiler includes a furnace, a burner that is provided on the wall surface of the furnace and that supplies and burns pulverized coal of fuel into the furnace, and a wall surface of the furnace downstream from the installation position of the burner.
  • a pulverized coal-fired boiler equipped with a after-air port that supplies combustion air to the interior of the furnace, a spray nozzle that supplies water or steam to the interior of the furnace is located near the combustion air outlet of After Airport.
  • water or steam or two fluids of water and steam are supplied to the inside of the furnace from the spray nozzle.
  • the pulverized coal fired boiler includes a furnace, a burner provided on the wall surface of the furnace to supply and burn pulverized coal of fuel into the furnace, and a fire downstream of the installation position of the burner.
  • a plurality of after-airports in the flow direction of the combustion gas in the furnace are arranged in a pulverized coal-fired boiler provided with a after-airport that is provided on the wall of the furnace and supplies combustion air into the furnace.
  • Water or steam, or two fluids of water and steam are supplied into the furnace from the after-air port installed upstream of the multiple installed after-air ports in the flow direction of the combustion gas. It is characterized by having constituted so.
  • the pulverized coal fired boiler according to the present invention has a combustion air supplied from a after air port installed upstream of the plurality of after air ports installed in the flow direction of the combustion gas in the furnace. It is characterized in that it is configured to supply with a reduced amount of air compared to the combustion air supplied from the after-air port installed downstream in the flow direction of the combustion gas.
  • the after-air port that supplies the water or steam, or two fluids of water and steam to the inside of the furnace, straightly emits combustion air as a straight flow therein.
  • a swirl flow channel installed on the outer peripheral side of the straight flow channel and ejecting combustion air as a swirl flow, and the water or steam, or the two fluids of water and steam Is ejected from the flow path of the swirling flow.
  • the pulverized coal burning boiler of the present invention includes a furnace, a burner provided on a wall surface of the furnace to supply and burn pulverized coal of fuel into the furnace, and a fire downstream of the installation position of the burner.
  • a pulverized coal-fired boiler equipped with a wind box with a after-air port that is provided on the wall of the furnace and supplies combustion air to the inside of the furnace and a duct pipe that leads the combustion air from the outside to the window box
  • a spray nozzle that supplies water or steam is installed inside the wind box or inside the duct pipe, and water or steam sprayed from the spray nozzle into the inside of the wind box or inside the duct pipe, or water and steam.
  • the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas is burned inside the furnace, and the thermal NOx generated during combustion is suppressed.
  • a highly reliable pulverized coal-fired boiler that reduces the concentration of coal can be realized.
  • FIG. 1 is a pulverized coal-fired boiler that burns pulverized coal as a fuel according to an embodiment of the present invention, and has a burner 2 and a spray nozzle 6 that has a spray nozzle 6 that sprays water and supplies combustion air.
  • a boiler system diagram of a pulverized coal fired boiler 100 equipped with a furnace 3 on the wall of the furnace 1 is shown.
  • a pulverized coal-fired boiler 100 has a furnace 1, and a pulverized coal of fuel is provided on the wall of the furnace 1, and a plurality of burners that mix combustion air with the pulverized coal and supply as fuel gas. 2 is provided.
  • a plurality of after airports 3 are provided on the wall surface of the furnace 1 at a position downstream of the position where the PANA 2 is installed.
  • Coal as the fuel for the pulverized coal-fired boiler 100 is pulverized into fine powder by a plurality of installed pulverized coal production devices 7 to be supplied to the PANA 2 through the pipe 7b, respectively.
  • the combustion air supplied through the duct pipe 4 and the pulverized coal are both injected into the furnace 1 from the burner 2 as fuel gas and burned.
  • Combustion air for burning the unburned unburned gas 10a out of the fuel gas introduced into the furnace 1 from the burner 2 is guided from the outside by the blower 12 to the heat exchanger 13. Then, heat is exchanged with the high-temperature exhaust gas 11 discharged from the furnace 1 to obtain a high-temperature air of about 300 ° C and supplied to the after-air port 3 through the duct pipe 14 as combustion air.
  • a part of the heat-exchanged high-temperature air is adjusted in flow distribution by a damper 8 provided in the middle of the duct pipe 14, and is installed on the wall surface of the furnace 1 to accommodate the parner 2 in the window. It is fed to box 4 and is put into the inside of furnace 1 from window box 4 as the outer air of PANA2.
  • a part of the high-temperature air is flow-distributed by the damper 9 and is introduced to the window box 5 which is installed on the wall surface of the furnace 1 and accommodates the after-air port 3 therein. As described above, the combustion air is fed into the furnace 1 through the after-air port 3.
  • the combustion gas 10 generated by burning the pulverized coal of the fuel inside the furnace 1 flows down the inside of the furnace 1 to the downstream side, becomes exhaust gas 11 outside the furnace 1, and is discharged through the pipe 14b.
  • a heat exchanger 13 is installed in the middle of the pipe 14b.
  • the exhaust gas 11 is subjected to heat treatment with the combustion air in the heat exchanger 13 and then subjected to denitration and desulfurization (not shown). Released from the communicating chimney 15 to the atmosphere.
  • a spray nozzle 6 is installed inside the after-air port 3 installed on the wall surface of the furnace 1, and water 18 that is a cooling fluid that suppresses the generation of thermal NOx generated when the fuel gas burns is supplied. Supply from the pump 16 to the spray nozzle 6 through the pipe 42.
  • the flow rate of the cooling fluid water 18 sprayed from the spray nozzle 6 to the inside of the furnace 1 is the exhaust gas 11 detected by the NOx detector 55 disposed in the pipe 14b for discharging the exhaust gas 11 from the furnace 1 to the outside. Based on NOx concentration! /, Configured to be adjustable!
  • the NOx concentration signal of the exhaust gas 11 detected by the NOx detector 55 is input to the control device 50, and the control device 50 compares the set desired NOX set value with the NOx concentration signal.
  • the flow rate command signal of the cooling fluid to be sprayed from the spray nozzle 6 is calculated inside the furnace 1 so that the NOx concentration of the exhaust gas 11 maintains the desired set value, and this command signal is sent from the control device 50 to the cooling fluid. It is configured to output to the flow rate adjusting valve 17 provided in the pipe 42 for supplying water 18 to the spray nozzle 6.
  • the opening of the valve 17 is received in response to the flow command signal calculated by the control device 50, and the spray nozzle 6 Increase the flow rate of the cooling fluid water 18 sprayed from to suppress the rise in flame temperature and reduce NOx.
  • the flow rate command signal calculated by the control device 50 is received and the opening of the valve 17 is operated to cool the cooling fluid.
  • the amount of water sprayed from the spray nozzle 6 is optimized, and efficient operation is performed.
  • the flow rate of the cooling fluid water 18 sprayed from the spray nozzle 6 to the inside of the furnace 1 is controlled according to the load of the pulverized coal-fired boiler 100 just corresponding to the NOx concentration of the exhaust gas 11. May be.
  • the load of the pulverized coal fired boiler 100 adjusts the flow rate of the cooling fluid water 18 sprayed from the spray nozzle 6 into the furnace 1 based on the boiler load signal instructed from the control room. Configure to be able to save.
  • the boiler load signal instructed from the control room is input to the control device 50, and the control device 50 commands the flow rate of the cooling fluid to be sprayed from the spray nozzle 6 in the furnace 1 in response to the boiler load.
  • the controller 50 calculates the flow rate of the cooling fluid by outputting the command signal from the control device 50 to the flow rate adjusting valve 17 provided in the piping 42 for supplying the cooling fluid to the spray nozzle 6. ! /
  • the opening of the valve 17 is set so that the flow rate of the cooling fluid water 18 is low and the flow rate of the water 18 is high when the load is high.
  • Configuration of the control device 50 that calculates the flow rate command signal of the cooling fluid to be sprayed from the spray nozzle 6 and outputs the valve opening command signal to the flow rate adjustment valve 17 to adjust the flow rate of the cooling fluid
  • the spray flow rate calculator to which the boiler load signal and the NOx detection value of the exhaust gas 11 detected by the NOx detector 55 are input to the control device 50. I have 53.
  • the control device 50 is also provided with a boiler load setting device 51 for setting the operation load of the boiler and a NOx concentration setting device 52 for setting the NOx concentration!
  • the spray flow rate calculator 53 of the control device 50 compares the boiler load signal with the load set value (threshold value) of the boiler load setter 51, and when the detected value exceeds the set value, The flow rate calculator 52 calculates the spray amount of the cooling fluid water 18 corresponding to the difference between the set value and the detected value, and outputs the opening degree of the valve 17 corresponding to this spray amount to the valve 17 as a command signal.
  • the spray nozzle 6 force is also configured to adjust the flow rate of water 18 sprayed into the furnace 1.
  • the spray flow rate calculator 53 of the control device 50 calculates the spray amount of the cooling fluid water 18 corresponding to the difference between the set value and the detected value, and responds to this spray amount.
  • the valve 17 is output to the valve 17 and sprayed from the spray nozzle 6 into the furnace 1. It is configured to regulate the flow rate of water 18.
  • FIG. 16 is a characteristic diagram that controls the valve that adjusts the cooling fluid.
  • the vertical axis of Fig. 16 (A) shows the NOx detection concentration of exhaust gas 11, the horizontal axis shows the opening degree of valve 17, the broken line shows the set value, and the solid line shows the characteristic of opening degree of valve 17 with respect to the NOx detection concentration. Each shows.
  • the vertical axis represents the boiler load
  • the horizontal axis represents the opening of the valve 17
  • the broken line represents the set value
  • the solid line represents the characteristic of the opening of the valve 17 with respect to the boiler load. ing.
  • the valve 17 when the detected value of the NOx detection concentration of the exhaust gas 11 is equal to or less than a set value (for example, the NOx emission regulation value) as controlled by the control device 50, the valve 17 The opening is set to 0 (closed) and water is not sprayed from the spray nozzle 6. NOx detection When the detected concentration value exceeds the set value, water is sprayed from the spray nozzle 6 by opening the valve 17 based on the opening of the valve 17 corresponding to the spray amount calculated according to the difference from the set value. Take control. In the figure, the NOx concentration and the opening degree of the valve 17 are not limited to this force.
  • the opening degree of the valve 17 is set to 0 ( Do not spray water from the spray nozzle 6.
  • the valve 17 is based on the opening of the valve 17 corresponding to the spray amount calculated according to the difference from the set value. Open and control to spray water from the spray nozzle 6.
  • the NOx concentration and the opening of the valve 17 are proportional to each other.
  • FIG. 2 is a partial structural diagram of the after air port in which the after air port 3 provided with the spray nozzle is applied to the pulverized coal burning boiler according to the embodiment of the present invention shown in FIG.
  • the after-air port 3 of this embodiment has a cylindrical shape facing one opening 3a of the after-air port 3 whose one end is installed in the wind box 5 and whose other end is open on the wall surface of the furnace 1.
  • a straight passage 30 is provided.
  • the after-air port 3 is provided with a frustoconical swirl passage 31 on the outer peripheral side of the straight passage 30, and the end of the swirl passage 31 is connected to the wall surface of the furnace 1. Form the outer edge of the opening 3a of the after-air port 3!
  • the straight flow 35 which is a part of the combustion air, is also introduced into the straight flow channel 30 by the hole force formed in the trunk of the straight flow channel 30, and the opening force at the tip of the straight flow channel 30 is also generated. Supplied inside furnace 1.
  • the swirl flow 36 which is a part of the combustion air, is swirled with the swirl strength adjusted by the register 32 provided in the frustum-shaped swirl flow path 31 provided on the outer peripheral side of the straight flow path 30. Opening force at the tip of the flow path 31 Supplied into the furnace 1.
  • a movable damper 33 is disposed outside the hole formed in the trunk portion of the straight flow path 30, and a movable damper 34 is also disposed on the upstream side of the turning flow path 31, By operating these dampers 33 and 3 4, the flow distribution of the combustion air flowing down the straight flow path 30 and the swirl flow path 31 is adjusted.
  • the spray nozzle 6 is installed at the jet outlet at the tip of the cylindrical straight passage 30 provided in the after-air port 3. Then, the spray nozzle 6 is disposed along the axis of the straight passage 30 so that the tip of the spray nozzle 6 is positioned in the vicinity of the opening 3a of the after-air port 3, and water 18 that is a cooling fluid is sprayed to the spray nozzle. It is injected into the furnace 1 from the tip of 6 to suppress NOx generation.
  • the after-air port 3 In the furnace 1 facing the opening 3a of the after-air port 3, the after-air port 3 is provided. As shown in FIG. 2, a combustion air jet 40 spreading from the opening 3a toward the center of the furnace 1 is formed by the combustion air supplied from the straight flow path 30 and the swirl flow path 31 respectively. .
  • the jet 40 of combustion air supplied from the straight passage 30 and the swirl passage 31 to the inside of the furnace 1 through the opening 3a of the after-air port 3 burns the inside of the furnace 1 from the position of the burner 2.
  • a mixing area 41 mixed with unburned gas 1 Oa containing unburned pulverized coal flowing down to the position of downstream air port 3 together with gas 10 is formed at the outer edge of combustion air jet 40 To do.
  • the combustion air supplied as the jet 40 and the unburned gas 10a are mixed to burn the unburned gas 10a, and the temperature of the formed flame rises to generate thermal NOx. To do.
  • the amount of thermal NOx produced is uniquely determined by the flame temperature during combustion, and production begins at about 1700K or higher.
  • the amount of thermal NOx produced is about a square of the rise in flame temperature, and the amount produced increases significantly as the temperature rises.
  • the cooling fluid water 18 introduced through the pipe 42 from the spray nozzle 6 disposed in the vicinity of the opening 3a of the after-air port 3 is sprayed to the spray area 18a so as to overlap the mixing area 41.
  • the latent heat of the water 18 sprayed in the spray area 18a that overlaps the mixing area 41, and the temperature of the flame in which the unburned gas 10a burns in the mixing area 41 due to sensible heat are removed. Since the increase is suppressed, the generation of thermal NOx in the mixing region 41 where the thermal NOx is most easily generated can be reduced.
  • the flame temperature of the unburned gas 10a combusted in the mixing region 41 is about 1600 K.
  • the spray nozzle 6 of the present embodiment is disposed in the vicinity of the opening 3a of the after-air port 3, ash adhesion to the spray nozzle or the contact of the structural material due to contact with high-temperature combustion gas. Deformation can be avoided, so that it is possible to obtain a highly reliable spray nozzle that can withstand long-term use.
  • the cooling fluid water 18 sprayed to the spray range 18a from the spray nozzle 6 toward the mixing region 41 formed inside the furnace 1 is the combustion air supplied from the after air port 3.
  • the spray nozzle 6 may be rotated and moved back and forth in the axial direction so that it can be sprayed accurately in the spray area 18a that overlaps with the mixing area 41 mixed with the unburned gas 10a according to the spread and shape of the jet 40 .
  • FIG. 3 shows an opening 3a of the after-air port 3 provided with a spray nozzle as seen from the arrows AA in FIG.
  • the water 18 of the cooling fluid is sprayed in the spray range 18a that overlaps the mixing region 41 of the jet 40 of combustion air supplied from the opening 3a of the after air port 3 shown in FIG. 2 and the unburned gas 10a.
  • the spray nozzle 6 sprays so as to spread concentrically.
  • the shape of the tip of the spray nozzle 6 is changed to be different from the spray pattern shown in FIG. 3, and water 18 is sprayed in a cone shape as one form of the spray range 18a as shown in FIG.
  • the moisture of the cooling fluid water 18 can be supplied to the spray range 18a that overlaps the mixing region 41 of the combustion air jet 40 and the unburned gas 10a, which is the NOx generation site, the same effect can be obtained.
  • the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and occurs during combustion. This makes it possible to realize a highly reliable pulverized coal fired boiler that reduces the concentration of thermal NOx.
  • FIG. 5 and FIG. 6 show partial structural views of an embodiment which is another structure of the after-air port employed in the pulverized coal burning boiler which is an embodiment of the present invention shown in FIG. .
  • FIG. 5 shows the structure of another embodiment of the after-air port provided with the spray nozzle
  • the configuration of the pulverized coal fired boiler adopting the after-airport 3 of this embodiment is the same as that of the pulverized coal fired boiler 100 of the embodiment shown in FIG. Omitted.
  • the structure of the after-air port 3 of this embodiment shown in FIGS. 5 and 6 is the same as that of the embodiment of the after-air port 3 shown in FIGS. Last Therefore, the description thereof is omitted, and only different portions will be described.
  • the spray nozzle 6 for spraying the cooling fluid water 18 is connected to the straight flow path 30.
  • a plurality of openings are arranged in the opening of the swirl flow path 31 on the outer peripheral side.
  • the tip of the spray nozzle 6 is disposed so as to be positioned in the vicinity of the opening 3a of the after air port 3 as in the configuration of the after air port 3 shown in the embodiment of FIG.
  • Cooling fluid water 18 can be accurately sprayed from the spray nozzle 6 to the mixing region 41 to be mixed in the spraying region 18a so as to overlap the mixing region 41.
  • the heat of the flame at which the unburned gas 10a burns in the mixing region 41 is deprived by the latent heat and sensible heat of the sprayed water 18 to increase the flame temperature by about 1600K or more.
  • the spray nozzle 6 of the present embodiment is also disposed in the vicinity of the opening 3a of the after-air port 3, ash adhesion to the spray nozzle or the contact of the structural material due to contact with high-temperature combustion gas It is possible to obtain a highly reliable spray nozzle that can avoid deformation and can withstand long-term use.
  • the spray of the necessary cooling fluid can be maintained by other spray nozzles, so it can withstand long-term use. It is possible to obtain a highly reliable spray nozzle.
  • FIG. 7 and FIG. 8 show partial structural views of still another embodiment of the after-airport employed in the pulverized coal fired boiler which is an embodiment of the present invention shown in FIG.
  • Fig. 7 shows the structure of still another embodiment of the after-air port provided with the spray nozzle
  • Fig. 8 shows the CC arrow view of Fig. 7, and the after-air port 3 of this embodiment is adopted.
  • the structure of the pulverized coal burning boiler is the same as that of the pulverized coal burning boiler 100 of the embodiment shown in FIG.
  • FIGS. 7 and 8 the structure of the after-air port 3 of this embodiment shown in FIGS. 7 and 8 is shown in FIGS. Since the basic configuration is the same as that of the embodiment of the after-air port 3 shown, the description of the common configuration will be omitted, and different portions will be described.
  • the spray nozzle 6 for spraying the cooling fluid water 18 is connected to the straight flow path 30.
  • a plurality of openings are arranged in the opening of the swirl flow path 31 on the outer peripheral side of the straight flow path 30, respectively.
  • the tip of each spray nozzle 6 is disposed in the vicinity of the opening 3a of the after air port 3 in the same manner as the after air port 3 shown in the embodiment of FIG.
  • the combustion air jet 40 and the unburned gas 10a are injected from the after air port 3 into the furnace 1 facing the opening 3a of the after air port 3.
  • the cooling fluid water 18 can be sprayed from the plurality of spray nozzles 6 to the mixing region 41 to be mixed more precisely and evenly in the spraying region 18 a that overlaps the mixing region 41.
  • the heat of the flame at which the unburned gas 10a burns in the mixing region 41 is taken away by the latent heat and sensible heat of the sprayed water 18 to increase the flame temperature by about 1600K or more.
  • the concentration of thermal NOx generated in the boiler can be reduced by about 10 to 30%.
  • the spray nozzle 6 of the present embodiment is also disposed in the vicinity of the opening 3a of the after-air port 3, ash adhesion to the spray nozzle or the contact of high-temperature combustion gas with the structural material Deformation can be avoided.
  • the spray of the required cooling fluid can be maintained by other spray nozzles, so it can withstand long-term use. Highly reliable! / It becomes possible to obtain a spray nozzle.
  • FIGs. 9 and 10 are partial structural views of another embodiment of the after-airport employed in the pulverized coal fired boiler as an embodiment of the present invention shown in Fig. 1.
  • FIG. 9 and FIG. 10 show the structure of another embodiment of the after-air port provided with the spray nozzle, respectively, and the configuration of the pulverized coal fired boiler in which the after-air port 3 of this embodiment is adopted is as follows. Since it is the same structure as the pulverized coal burning boiler 100 of the Example shown in FIG. 1, description is abbreviate
  • the structure of the after-air port 3 of the present embodiment shown in FIGS. 9 and 10 is the same as each of the embodiments of the after-air port 3 shown in FIGS. The description of this configuration is omitted, and only the differences are described.
  • the spray nozzle 6 that sprays the cooling fluid water 18 installed in the after air port 3 of each embodiment has the position of the tip of the spray nozzle 6 as the opening of the after air port 3. It is arranged so that it is located closer to the wall of the wind box 5 from 3a and away from the furnace 1.
  • the tip of the spray nozzle 6 is located at the tip of the after-air port 3a, and the jet of combustion air 40 It is arranged at the position inside the after-air port 3a on the upstream side of the.
  • the cooling fluid water 18 is sprayed from the spray nozzle 6 at the upstream position of the jet 40 of combustion air supplied into the furnace 1 from the opening 3 a of the after air port 3.
  • the water is added to the combustion air jet 40 itself supplied from the after-air port by vaporizing and mixing water into the combustion air jet 40 supplied from the after-air port 3 more evenly. It is possible to supply moisture to the spraying region 41 that overlaps with the mixing region 41 where the unburned gas 10a and 40 are mixed, and to prevent the rise in the flame temperature more reliably.
  • the spray nozzle 6 installed in the after-air port 3 of the present embodiment has a force S indicating a spray nozzle for spraying water 18 as a cooling fluid, and the cooling fluid of water 18 and steam 20. It can also be applied to a two-fluid spray nozzle.
  • control of the cooling fluid by the spray nozzle 6 installed in the after air port 3 of the present embodiment shown in FIGS. 9 and 10 is the same as in each of the embodiments described above. This is done by adjusting the flow rate of the cooling fluid by the control device 50.
  • the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and occurs during combustion.
  • a reliable pulverized coal fired boiler that reduces the concentration of thermal NOx can be realized.
  • FIG. 11 shows a wall surface of the furnace 1 that includes a burner 2 that burns pulverized coal as a fuel and a after-air port 3 that has a spray nozzle 6 that sprays both water and steam and supplies combustion air.
  • the configuration of the pulverized coal burning boiler of this embodiment is the same as that of the pulverized coal burning boiler 100 of the embodiment shown in FIG.
  • the two-fluid nozzle capable of spraying two fluids of water 18 and steam 20 is applied to the spray nozzle 6 provided in the after-air port 3. Zunore is adopted.
  • a steam system that supplies steam 20 to the spray nozzle 6 that sprays two fluids is a steam tank that guides and stores part of the steam used in the power plant and sets it to a predetermined pressure. And a pipe 43 for supplying the steam 20 stored in the steam tank 21 to the spray nozzle 6, and a valve 22 for adjusting the amount of steam 20 to be supplied is installed in the pipe 43.
  • the opening degree of the valve 22 for adjusting the amount of steam 20 sprayed from the two-fluid spray nozzle 6 into the furnace 1 is controlled by the control device 50
  • the valve for adjusting the spray amount of water 18 Similarly to the control of the opening degree 17, the control device 50 uses the NOx concentration setter 52 and the boiler load in the spray flow rate calculator 53 according to the NOx emission concentration of the exhaust gas 11 detected by the NOx detector 55 and the boiler load.
  • the amount of steam 20 that needs to be supplied is calculated by comparing each setting value of the setting device 51, and the opening of the valve 22 corresponding to this amount of steam is used as the opening signal to calculate the spray flow rate calculator 53 of the control device 50.
  • the required amount of steam 20 is sprayed from the spray nozzle 6 as a command to the valve 22.
  • the state of spraying of the steam 20 sprayed from the two-fluid spray nozzle 6 into the furnace 1 is the same as the spray range 18a superimposed on the mixing region 41 shown by the spray nozzle 6 in Figs. It is.
  • control of the valve opening degree of the valve 22 by the control device 50 is based on the control of the valve opening degree of the valve 17 by the control device 50 shown in Fig. 16 (A) and Fig. 16 (B). It becomes.
  • the flow rate of the steam 20 sprayed from the spray nozzle 6 spraying the two fluids of the water 18 and the steam 20 is changed in the flow rate of the water 18 to be sprayed.
  • the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and is generated during combustion. It is possible to realize a highly reliable pulverized coal fired boiler that reduces the concentration of thermal NOx.
  • FIG. 12 shows the present invention in which a burner 2 for burning pulverized coal of fuel, a after air port 3 for supplying combustion air, and a spray nozzle 6 for spraying water of cooling fluid to the after air port 3 are further provided.
  • It is a boiler system diagram which shows the structure of the pulverized coal burning boiler 100 which is another Example.
  • the basic configuration of the pulverized coal fired boiler 100 of the present embodiment is the same as that of the pulverized coal fired boiler 100 of the embodiment shown in Fig. 1, so that the description thereof will be omitted and only the differences will be described.
  • FIG. 13 and FIG. 14 show the structure of the wind box 5 in which the after-air port 3 employed in the pulverized coal burning boiler 100 of the embodiment of the present invention shown in FIG. 13 shows the structure of the window box 5 of this embodiment in which the after-air port 3 is housed, and FIG. 14 shows a DD arrow view of FIG.
  • the spray nozzle 6 is arranged on the wall surface of the wind box 5, and water 18 as a cooling fluid is supplied from the spray nozzle 6 to the spray range 18 a in the wind box 5. Spray.
  • the temperature in the wind box 5 of the combustion air injected as a jet 40 into the furnace 1 from the opening 3a of the after-air port 3 accommodated in the wind box 5 is about 300 ° C.
  • the water 18 sprayed from the spray nozzle 6 to the spray range 18a in the wind box 5 has a sufficiently high temperature to be vaporized by the combustion air.
  • the water 18 vaporized in the wind box 5 is sufficiently mixed in the air flow of the combustion air in the wind box 5, and the combustion air is introduced into the furnace 1 from the opening 3a of the after air port 3. It is supplied as a part of the jet 40 and is supplied to the mixing region 41 where the jet 40 of combustion air and the unburned gas 10a are mixed to lower the temperature of the flame where the unburned gas 10a burns.
  • the combustion air jet 40 jetted into the furnace 1 facing the opening 3a of the after-airport 3 is mixed with the mixing region 41 where the unburned gas 10a is mixed.
  • the combustion air jet 40 in which the cooling fluid water 18 sprayed and vaporized from the spray nozzle 6 into the wind box 5 is mixed.
  • the temperature of the flame of the unburned gas 10a burning in the mixing region 41 is deprived by the latent heat of the water 18 of the water 18 sprayed from the spray nozzle 6 and the sensible heat. It is possible to more reliably control the rise in the temperature to about 1600K or less, preferably about 1600K to about 1400K, thus reducing the concentration of thermal NOx generated in the boiler by about 10-30%. Force S is possible.
  • the spray pattern is not particularly limited as long as the cooling fluid water 18 sprayed from the spray nozzle 6 in the wind box 5 can be vaporized. Moreover, it is not necessary for all the sprayed water 18 to be vaporized, and the water 18 remaining in the wind box 5 can be recovered as drainage and reused.
  • water 18 sprayed from the spray nozzle 6 in the wind box 5 is vaporized, and water is uniformly mixed into the jet 40 itself injected into the furnace 1 from the after-air port 3.
  • moisture can be reliably supplied to the mixing region 41 and an increase in the flame temperature combusting in the mixing region 41 can be suppressed.
  • the temperature of the combustion air in the wind box 5 decreases due to evaporation of the sprayed water, and the jet 40 itself injected into the furnace 1 from the after-air port 3 becomes low temperature. There is an advantage that the rise in the temperature of the burning flame can be more reliably suppressed.
  • the cooling fluid sprayed from the spray nozzle 6 is water 18.
  • steam 20 or two fluids of water and steam may be sprayed.
  • control of the cooling fluid by the spray nozzle 6 installed in the wind box 5 of the present embodiment is performed by controlling the flow rate of the cooling fluid by the control device 50 in the same manner as each of the embodiments described above. This is done by adjusting.
  • the supply of combustion air from the after-airport reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and occurs during combustion.
  • a reliable pulverized coal fired boiler that reduces the concentration of thermal NOx can be realized.
  • FIG. 17 is a diagram of spraying cooling fluid water onto a burner 2 that burns pulverized coal fuel, after-air port 3 that supplies combustion air, and duct pipe 14 that supplies combustion air to after-air port 3
  • FIG. 4 is a boiler system diagram showing a configuration of a pulverized coal fired boiler 100 according to another embodiment of the present invention in which a spray nozzle 6 is provided.
  • the basic configuration of the pulverized coal burning boiler 100 of the present embodiment is the same as that of the pulverized coal burning boiler 100 of the embodiment shown in Fig. 1, so that the description thereof will be omitted and only the differences will be described.
  • a spray nozzle 6 is installed in the duct pipe 14 located further upstream than the wind box 5 for supplying combustion air to the after air port 3, and the spray nozzle 6 is cooled. Since the fluid water 18 is sprayed on the combustion air flowing inside the duct pipe 14, the residence time of the sprayed water 18 mixed with the high-temperature combustion air supplied to the after-air port 3 increases.
  • the vaporization rate of the water 18 sprayed from the spray nozzle 6 is improved and less draining is required, so that the cooling fluid water 18 sprayed from the spray nozzle 6 is more efficiently vaporized.
  • water 18 is sprayed from the spray nozzle 6 in the duct pipe 14 upstream of the wind box 5 to vaporize it, and the jet 40 itself injected into the furnace 1 from the after air port 3
  • uniformly mixing moisture it is possible to reliably supply moisture to the mixing region 41, and to suppress an increase in the flame temperature that burns in the mixing region 41.
  • the temperature of the combustion air supplied into the wind box 5 is lowered by evaporation of the sprayed water, and the jet 40 itself injected into the furnace 1 from the after-air port 3 becomes a low temperature. in some merit force s that increase of flame temperature for combustion can be more reliably suppressed.
  • cooling fluid sprayed from the spray nozzle 6 is water 18
  • steam 20 or two fluids of water and steam may be sprayed.
  • control of the cooling fluid by the spray nozzle 6 installed in the window box 5 of the present embodiment is performed by controlling the flow rate of the cooling fluid by the control device 50 in the same manner as each of the embodiments described above. This is done by adjusting.
  • the temperature of the flame at which the unburned gas 10a burns in the mixing region 41 is deprived by the latent heat of water 18 of the water 18 sprayed from the spray nozzle 6 and the sensible heat. It is possible to more reliably control the rise in the temperature to about 1600K or less, preferably about 1600K to about 1400K, thus reducing the concentration of thermal NOx generated in the boiler by about 10-30%. Force S is possible.
  • the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and occurs during combustion. It is possible to realize a highly reliable pulverized coal fired boiler that reduces the concentration of thermal NOx.
  • FIG. 18 shows combustion with a burner 2 for injecting and burning fuel pulverized coal, a main after-air port 61 for supplying combustion air, and a spray nozzle 6 for spraying both water and steam.
  • Sky FIG. 3 is a boiler system diagram showing a configuration of a pulverized coal fired boiler 100 which is still another embodiment of the present invention in which an auxiliary after-air port 60 for supplying air is provided on the wall surface of the furnace 1.
  • the configuration of the pulverized coal fired boiler of this example is the pulverized coal fired boiler of the example shown in FIG.
  • the sub-after-airport 60 is provided upstream of the wall surface of the furnace 1 along the flow direction of the combustion gas 10 flowing inside the furnace 1.
  • the main after-air port 61 is installed downstream.
  • sub-after air port 60 is provided with a spray nozzle 6, and the spray nozzle 6 is configured to spray water or both water and steam.
  • the amount of air supplied from the sub-after air port 60 is set to be smaller than the amount of air supplied from the main after-air port 61.
  • the air flow 62 blown into the furnace 1 from the auxiliary after-airport 60 and supplied to the furnace 1 flows downstream along the inner wall surface of the furnace 1 because the flow rate of the blown air is small.
  • the air flow 63 ejected from the main after-air port 61 reaches the central part inside the furnace 1 due to the large flow rate of ejection.
  • the temperature of the combustion gas at the time of mixing with the combustion gas 10a out of the air flows 62 and 63 near the wall of the furnace 1 with respect to the combustion gas 10a flowing from upstream to downstream Is higher in the upstream air flow 62.
  • the water sprayed from the spray nozzle 6 takes the heat of evaporation from the surrounding air during evaporation, and lowers the temperature of the air.
  • the air flow 62 contains a lot of water and the specific heat increases, the air flow 62 ejected from the sub-after air port 60 and the combustion gas 10a are mixed with each other. Combustion reaction can be suppressed by the moisture contained in 62 so that the combustion temperature can be kept low.
  • a part of the air flow 62 containing moisture after mixing with the combustion gas 10a is ejected from the main after-air port 61 located downstream thereof. Mix with air stream 63.
  • the air flow 62 supplied from the sub-after air port 60 installed on the upstream side of the furnace 1 is the air flow supplied from the main after-air port 61 installed on the downstream side 63 air
  • the flow of air supplied from the upstream secondary air port 60 is the same as the flow of air supplied from the main after air port 61. Even when it is set to be larger than the amount of air, it is possible to obtain substantially the same results.
  • the amount of water sprayed from the spray nozzle 6 provided in the sub-lifter air port 60 is larger than that described above as described above. It is self-explanatory.
  • the cooling fluid sprayed from the spray nozzle 6 is water 18.
  • steam 20 or two fluids of water 18 and steam 20 are sprayed. It's okay.
  • the force S is shown when the position of the tip of the spray nozzle 6 is provided in the opening of the sub-after air port 60, and in Embodiment 6 and Figure 17 of the present invention shown in FIG.
  • the above-mentioned spray nozzle 6 is also installed in the wind box 5a for accommodating the auxiliary after-air port 60 and the duct pipe 14 for supplying air to the window box 5a. An effect is obtained.
  • the spray nozzle 6 can be provided at the opening of the swirl flow path 31 on the outer peripheral side of the straight flow path 30. It is.
  • the water 18 ejected from the spray nozzle 6 by the swirling flow flows in a large amount in the outer peripheral portion of the air flow 62, so that the water content in the mixed portion of the combustion gas 10a and the air flow 62 increases. Therefore, it is possible to reduce the concentration of thermal NOx with a small amount of water used.
  • the control of the cooling fluid sprayed from the spray nozzle 6 provided in the auxiliary after-air port 60 is controlled by the control device 50 in the same manner as in each of the embodiments described above. This is done by adjusting the flow rate of the fluid to an appropriate amount.
  • the NOx concentration signal of the exhaust gas 11 detected by the NOx detector 55 is input to the control device 50, and the desired NOX set value set by the control device 50 is compared with the NOx concentration signal.
  • the flow rate command signal of the cooling fluid to be sprayed from the spray nozzle 6 is calculated in the furnace 1 so that the NOx concentration of the exhaust gas 11 maintains the desired set value, and this command signal is used as the spray fluid water 18 spray nozzle. It is configured to output to the flow rate adjustment valve 17 provided in the pipe 42 to be supplied to 6, and the flow rate of the cooling fluid is adjusted to an appropriate amount to reduce the concentration of thermal NOx.
  • the present invention relates to a pulverized coal fired boiler that uses pulverized coal as a fuel, and is particularly applicable to a pulverized coal fired boiler that suppresses the formation of thermal nitrogen oxides, and also to an existing pulverized coal fired boiler. Easy to apply.
  • FIG. 1 is a boiler system diagram showing the configuration of a pulverized coal fired boiler according to an embodiment of the present invention.
  • 1 is a structural diagram of a after airport according to an embodiment of the present invention.
  • FIG. 2 is a cross-sectional view showing the structure of a after-airport provided with a spray nozzle applied to the pulverized coal fired boiler of one embodiment of the present invention shown in FIG.
  • FIG. 3 AA arrow view of the after-airport equipped with the spray nozzle shown in FIG.
  • FIG. 4 is a diagram showing an example of a spray pattern of a spray nozzle provided in the after air port shown in FIG. 2.
  • FIG. 5 shows a spray nozzle applied to the pulverized coal fired boiler according to the embodiment of the present invention shown in FIG. Sectional drawing which shows the other structure of the after airport provided.
  • FIG. 6 is a BB arrow view of the after air port equipped with the spray nozzle shown in FIG.
  • FIG. 7 is a cross-sectional view showing still another structure of the after-airport provided with the spray nozzle applied to the pulverized coal burning boiler of one embodiment of the present invention shown in FIG.
  • FIG. 8 is a CC arrow view of the after air port equipped with the spray nozzle shown in FIG.
  • FIG. 9 is a cross-sectional view showing another structure of a after-airport provided with a spray nozzle applied to the pulverized coal fired boiler of one embodiment of the present invention shown in FIG.
  • FIG. 10 is a cross-sectional view showing still another structure of the after-airport provided with the spray nozzle that is applied to the pulverized coal burning boiler of the embodiment of the present invention shown in FIG.
  • FIG. 11 is a boiler system diagram showing the configuration of a pulverized coal fired boiler according to another embodiment of the present invention.
  • FIG. 12 is a boiler system diagram showing the configuration of a pulverized coal fired boiler according to still another embodiment of the present invention.
  • FIG. 13 is a cross-sectional view showing the structure of a wind box provided with a spray nozzle applied to a pulverized coal fired boiler as still another embodiment of the present invention shown in FIG.
  • FIG. 14 is a DD arrow view of a wind box provided with the spray nozzle shown in FIG.
  • FIG. 15 is a block diagram showing a control device that controls the spray amount of the cooling fluid provided in the pulverized coal fired boiler of one embodiment of the present invention shown in FIG. 1.
  • FIG. 16 A characteristic diagram for controlling the valve for adjusting the cooling fluid in the control device shown in FIG. 15 is shown.
  • (A) in FIG. 16 shows the relationship between the NOx concentration of the exhaust gas and the opening degree of the valve.
  • Fig. 16B is a characteristic diagram showing the relationship between the valve opening and the boiler load.
  • FIG. 17 is a boiler system diagram showing a configuration of a pulverized coal burning boiler that is another embodiment of the present invention.
  • FIG. 18 is a boiler system diagram showing the configuration of a pulverized coal fired boiler which is still another embodiment of the present invention.

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Abstract

A pulverized coal boiler of high reliability that attains assured inhibition of any increase of flame temperature occurring at combustion of unburned gas inside furnace by supply of combustion air from an after-air port and attains lowering of the concentration of thermal NOx occurring at combustion. The pulverized coal boiler is pulverized coal boiler (100) comprising furnace (1); burner (2) for feeding of pulverized coal as a fuel into the furnace and combustion thereof, provided on a wall surface of the furnace; and after-air port (3,61) for feeding of combustion air into the interior of the furnace, provided on a wall surface of the furnace downstream of the position at which the burner is provided, wherein spray nozzle (6) for feeding of water, or steam, or two fluids of water and steam into the interior of the furnace is disposed in the vicinity of combustion air injection hole of the after-air port (3,60) so that together with the combustion air fed from the after-air port, water, or steam, or two fluids of water and steam are fed from the spray nozzle into the interior of the furnace.

Description

明 細 書  Specification
微粉炭焚きボイラ  Pulverized coal fired boiler
技術分野  Technical field
[0001] 本発明は、燃料として微粉炭を使用する微粉炭焚きボイラに係り、特にサーマル窒 素酸化物の生成を抑制する微粉炭焚きボイラに関する。  The present invention relates to a pulverized coal fired boiler that uses pulverized coal as a fuel, and more particularly to a pulverized coal fired boiler that suppresses the generation of thermal nitrogen oxides.
背景技術  Background art
[0002] 微粉炭焚きボイラでは燃料の微粉炭を燃焼させる際に発生する NOx濃度の抑制 が求められるため二段燃焼法が主流となっている。  [0002] In pulverized coal fired boilers, the two-stage combustion method has become the mainstream because it is required to suppress the concentration of NOx generated when burning pulverized coal as fuel.
[0003] 二段燃焼法とは、例えば特開平 6— 201105号公報に開示されているように、微粉 炭焚きボイラの火炉に微粉炭パーナと、このパーナの下流にァフタエアポートが夫々 設けられ、パーナからは燃料の微粉炭と燃焼用空気が供給され、ァフタエアポートか らは燃焼用空気が供給される構成の微粉炭焚きボイラに適用されている。  [0003] In the two-stage combustion method, for example, as disclosed in Japanese Patent Laid-Open No. 6-201105, a pulverized coal burner is provided in a furnace of a pulverized coal burning boiler, and a after-air port is provided downstream of the burner. The pulverized coal and combustion air are supplied from the PANA, and the combustion air is supplied from the after airport to the pulverized coal fired boiler.
[0004] 即ち、パーナ部での燃焼では、燃料の微粉炭を完全燃焼させるために必要な理論 空気比以下となる量の燃焼用空気を微粉炭と共に燃料ガスとしてパーナから供給し 、火炉の内部で空気不足の状態で燃料ガス中の微粉炭を燃焼させて還元雰囲気と し、燃焼時に発生する NOxを窒素に還元して NOx生成を抑える。  [0004] That is, in the combustion in the PANA section, an amount of combustion air that is less than the theoretical air ratio required for complete combustion of the pulverized coal of fuel is supplied from the PANA as fuel gas together with the pulverized coal, and the interior of the furnace In this situation, the pulverized coal in the fuel gas is burned in a reducing atmosphere to create a reducing atmosphere, and NOx generated during combustion is reduced to nitrogen to suppress NOx generation.
[0005] この還元雰囲気では酸素不足によってパーナから火炉に供給された燃料ガス中の 微粉炭に未燃分が残り、 CO (—酸化炭素）が発生する。そこで、この還元雰囲気で 発生した未燃分の微粉炭及び COを完全燃焼させるため、パーナの下流に位置する ァフタエアポートから、理論空気比の不足分となる空気量より若干多めの燃焼用空気 を火炉内に供給して未燃分の微粉炭及び COを燃焼し、 NOx及び COの生成を低減 させるようにした燃焼法である。  [0005] In this reducing atmosphere, due to lack of oxygen, unburned coal remains in the pulverized coal in the fuel gas supplied from the PANA to the furnace, and CO (-carbon oxide) is generated. Therefore, in order to completely burn the unburned pulverized coal and CO generated in this reducing atmosphere, the combustion air is slightly larger than the amount of air that is insufficient for the theoretical air ratio from the after air port located downstream of the burner. This is a combustion method that supplies unburned pulverized coal and CO to the furnace and reduces the production of NOx and CO.
[0006] そして、燃料の微粉炭を燃焼した燃焼ガスが火炉内を流下するようにし、この流下 する燃焼ガスと火炉に設置された熱交換器（図示せず）とが熱交換して燃焼ガスから 熱量を取り出し、低温となった燃焼ガスを火炉力 排ガスとして微粉炭焚きボイラの外 部に排出する。 [0006] The combustion gas combusted by the pulverized coal of fuel flows down in the furnace, and the combustion gas flowing down and the heat exchanger (not shown) installed in the furnace exchange heat to produce the combustion gas. The amount of heat is taken out of the gas, and the low-temperature combustion gas is discharged outside the pulverized coal-fired boiler as furnace power exhaust gas.
[0007] ところでボイラで生成する NOxはフューエル NOxとサーマル NOxに大別される。フ ユーエル NOxは燃料である石炭に含まれる窒素化合物が酸化することで生成する。 このフューエル NOxはパーナでの燃焼技術の改善により大幅に低減されて!/、る。一 方、サーマル NOxは空気中に含まれる窒素が高温下で酸化することで生成する。 [0007] By the way, NOx generated in a boiler is roughly classified into fuel NOx and thermal NOx. F Yuel NOx is generated by the oxidation of nitrogen compounds contained in coal as fuel. This fuel NOx is greatly reduced by improving combustion technology in the PANA! On the other hand, thermal NOx is generated by the oxidation of nitrogen contained in the air at high temperatures.
[0008] 近年、フューエル NOxの低減によりこのサーマル NOxの生成量も無視できなくな つており、さらなる NOx低減を実現するにはサーマル NOxの低減が必須となってき ている。 [0008] In recent years, the generation amount of this thermal NOx has become nonnegligible due to the reduction of fuel NOx, and in order to realize further NOx reduction, the reduction of thermal NOx has become essential.
[0009] 特開 2003— 322310号公報には、このサーマル NOxの低減を目的として最上段 のパーナより上方で且つ熱交換器の二次過熱器より下方の燃焼温度が高くて熱負 荷の高くなる火炉中央部に火炉壁面から駆動装置を備えた抜き差し自在の噴霧ノズ ルを揷入して、この噴霧ノズルから前記した火炉中央部に水又は蒸気を噴霧して燃 焼ガスの火炎温度を低下させる技術が開示されている。  [0009] Japanese Patent Laid-Open No. 2003-322310 discloses that for the purpose of reducing this thermal NOx, the combustion temperature is higher than the uppermost burner and below the secondary superheater of the heat exchanger, and the heat load is high. Insert a removable spray nozzle equipped with a drive device from the furnace wall into the center of the furnace and spray water or steam from the spray nozzle onto the center of the furnace to lower the flame temperature of the combustion gas. Techniques for making them disclosed are disclosed.
[0010] 特許文献 1 :特開平 6— 201105号公報  Patent Document 1: Japanese Patent Laid-Open No. 6-201105
特許文献 2 :特開 2003— 322310号公報  Patent Document 2: Japanese Patent Laid-Open No. 2003-322310
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0011] しかしながら、特開 2003— 322310号公報に開示された技術では、火炉壁面に設 置した抜き差し自在の噴霧ノズルから燃焼温度が高くて熱負荷の高くなる火炉中央 部に水又は蒸気を噴霧して火炎温度を低下させようとしている力 このような構造の 噴霧ノズルを火炉壁面に設置する方式では火炉内部のサーマル NOxが生成する火 炎温度が高レ、領域はボイラの負荷によって変動するので、この火炎温度が高レ、領域 に水又は蒸気を確実に噴霧して火炎温度を低下させることは火炉壁面に多数の噴 霧ノズルを設置しない限り困難であり、よってサーマル NOxを十分に低減させること は困難である。 [0011] However, in the technique disclosed in Japanese Patent Laid-Open No. 2003-322310, water or steam is sprayed from the removable spray nozzle installed on the furnace wall surface to the center of the furnace where the combustion temperature is high and the heat load is high. Force to lower the flame temperature by installing a spray nozzle with such a structure on the wall of the furnace, the flame temperature generated by the thermal NOx inside the furnace is high, and the region varies depending on the load of the boiler. Therefore, it is difficult to reduce the flame temperature by reliably spraying water or steam in the area where the flame temperature is high, unless a large number of spray nozzles are installed on the wall of the furnace, thus reducing the thermal NOx sufficiently. It is difficult.
[0012] また、水又は蒸気を供給する噴霧ノズルを抜き差し自在とするための駆動装置を噴 霧ノズルに備えさせる必要があり、噴霧ノズルの構造が複雑となるので機器のメンテ ナンスなどコストアップとなる。更に、火炉の内部への噴霧ノズルの長時間の揷入は、 噴霧ノズルへの灰付着や、高温の燃焼ガスとの接触による構造材の変形などで噴霧 ノズルとして長期間の使用に耐えられるのか信頼性に懸念が残る。 [0013] 本発明の目的は、ァフタエアポートからの燃焼用空気の供給によって火炉内部で 未燃ガスが燃焼する際に生じる火炎温度の上昇を確実に抑制し、燃焼時に発生する サーマル NOxの濃度を低減する信頼性の高い微粉炭焚きボイラを提供することにあ [0012] In addition, it is necessary to provide the spray nozzle with a drive device for allowing the spray nozzle to supply water or steam to be freely inserted and removed, which complicates the structure of the spray nozzle and increases the cost of equipment maintenance. Become. Furthermore, is the long-term penetration of the spray nozzle into the furnace resistant to long-term use as a spray nozzle due to ash adhesion to the spray nozzle or deformation of the structural material due to contact with high-temperature combustion gas? Concerns remain about reliability. [0013] An object of the present invention is to reliably suppress an increase in flame temperature that occurs when unburned gas is burned in the furnace by supplying combustion air from the after-air port, and the concentration of thermal NOx generated during combustion. To provide a highly reliable pulverized coal fired boiler
課題を解決するための手段 Means for solving the problem
[0014] 本発明の微粉炭焚きボイラは、火炉と、この火炉の壁面に設けられて燃料の微粉 炭を火炉内に供給して燃焼させるパーナと、パーナの設置位置より下流側の火炉の 壁面に設けられて燃焼用空気を火炉の内部に供給するァフタエアポートを備えた微 粉炭焚きボイラにおいて、水又は蒸気を火炉の内部に供給する噴霧ノズルをァフタ エアポートの燃焼用空気の噴出口の近傍に設けて、ァフタエアポートから供給される 燃焼用空気と共に噴霧ノズルから水又は蒸気、又は水と蒸気の二流体を火炉の内 部に供給するように構成したことを特徴とする。  [0014] A pulverized coal burning boiler according to the present invention includes a furnace, a burner that is provided on the wall surface of the furnace and that supplies and burns pulverized coal of fuel into the furnace, and a wall surface of the furnace downstream from the installation position of the burner. In a pulverized coal-fired boiler equipped with a after-air port that supplies combustion air to the interior of the furnace, a spray nozzle that supplies water or steam to the interior of the furnace is located near the combustion air outlet of After Airport. In addition to the combustion air supplied from the after-air port, water or steam or two fluids of water and steam are supplied to the inside of the furnace from the spray nozzle.
[0015] また、本発明の微粉炭焚きボイラは、火炉と、この火炉の壁面に設けられて燃料の 微粉炭を火炉内に供給して燃焼させるパーナと、パーナの設置位置より下流側の火 炉の壁面に設けられて燃焼用空気を火炉の内部に供給するァフタエアポートを備え た微粉炭焚きボイラにぉレ、て、前記ァフタエアポートを前記火炉内の燃焼ガスの流 れ方向に複数設置し、前記複数設置したァフタエアポートのうち、前記火炉内の燃 焼ガスの流れ方向の上流側に設置したァフタエアポートから水又は蒸気、又は水と 蒸気の二流体を火炉の内部に供給するように構成したことを特徴とする。  [0015] Further, the pulverized coal fired boiler according to the present invention includes a furnace, a burner provided on the wall surface of the furnace to supply and burn pulverized coal of fuel into the furnace, and a fire downstream of the installation position of the burner. A plurality of after-airports in the flow direction of the combustion gas in the furnace are arranged in a pulverized coal-fired boiler provided with a after-airport that is provided on the wall of the furnace and supplies combustion air into the furnace. Water or steam, or two fluids of water and steam are supplied into the furnace from the after-air port installed upstream of the multiple installed after-air ports in the flow direction of the combustion gas. It is characterized by having constituted so.
[0016] また、本発明の微粉炭焚きボイラは、前記複数設置したァフタエアポートのうち、前 記火炉内の燃焼ガスの流れ方向の上流側に設置したァフタエアポートから供給する 燃焼用空気は、燃焼ガスの流れ方向の下流側に設置したァフタエアポートから供給 する燃焼用空気に比べて空気量を少なくして供給するように構成したことを特徴とす  [0016] Further, the pulverized coal fired boiler according to the present invention has a combustion air supplied from a after air port installed upstream of the plurality of after air ports installed in the flow direction of the combustion gas in the furnace. It is characterized in that it is configured to supply with a reduced amount of air compared to the combustion air supplied from the after-air port installed downstream in the flow direction of the combustion gas.
[0017] また、本発明の微粉炭焚きボイラは、前記水又は蒸気、水と蒸気の二流体を火炉 の内部に供給するァフタエアポートは、その内部に燃焼用空気を直進流として噴出 する直進流の流路と、この直進流の流路の外周側に設置されて燃焼用空気を旋回 流として噴出する旋回流の流路とを備え、前記水又は蒸気、又は水と蒸気の二流体 を前記旋回流の流路から噴出させるように構成したことを特徴とする。 [0017] Further, in the pulverized coal fired boiler of the present invention, the after-air port that supplies the water or steam, or two fluids of water and steam to the inside of the furnace, straightly emits combustion air as a straight flow therein. And a swirl flow channel installed on the outer peripheral side of the straight flow channel and ejecting combustion air as a swirl flow, and the water or steam, or the two fluids of water and steam Is ejected from the flow path of the swirling flow.
[0018] また、本発明の微粉炭焚きボイラは、火炉と、この火炉の壁面に設けられて燃料の 微粉炭を火炉内に供給して燃焼させるパーナと、パーナの設置位置より下流側の火 炉の壁面に設けられて燃焼用空気を火炉の内部に供給するァフタエアポートを有す るウィンドボックスと、このウィンドボックスに外部から燃焼用空気を導くダクト配管を備 えた微粉炭焚きボイラにお!/、て、水又は蒸気を供給する噴霧ノズルをウィンドボックス の内部又はダクト配管の内部に設け、この噴霧ノズルからウィンドボックスの内部又は ダクト配管の内部に噴霧した水又は蒸気、又は水と蒸気の二流体をウィンドボックス に備えたァフタエアポートの噴出ロカ、ら燃焼用空気と共に火炉の内部に供給するよ うに構成したことを特徴とする。 [0018] Further, the pulverized coal burning boiler of the present invention includes a furnace, a burner provided on a wall surface of the furnace to supply and burn pulverized coal of fuel into the furnace, and a fire downstream of the installation position of the burner. A pulverized coal-fired boiler equipped with a wind box with a after-air port that is provided on the wall of the furnace and supplies combustion air to the inside of the furnace and a duct pipe that leads the combustion air from the outside to the window box A spray nozzle that supplies water or steam is installed inside the wind box or inside the duct pipe, and water or steam sprayed from the spray nozzle into the inside of the wind box or inside the duct pipe, or water and steam. These two fluids are supplied to the inside of the furnace together with the combustion air from the after-air port jet loca provided in the wind box.
発明の効果  The invention's effect
[0019] 本発明によれば、ァフタエアポートからの燃焼用空気の供給によって火炉内部で未 燃ガスが燃焼する際に生じる火炎温度の上昇を確実に抑制し、燃焼時に発生するサ 一マル NOxの濃度を低減する信頼性の高い微粉炭焚きボイラを実現することが出来 発明を実施するための最良の形態  [0019] According to the present invention, the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas is burned inside the furnace, and the thermal NOx generated during combustion is suppressed. A highly reliable pulverized coal-fired boiler that reduces the concentration of coal can be realized. BEST MODE FOR CARRYING OUT THE INVENTION
[0020] 次に本発明の一実施例である微粉炭焚きボイラについて図面を用いて説明する。  Next, a pulverized coal fired boiler as an embodiment of the present invention will be described with reference to the drawings.
実施例 1  Example 1
[0021] 図 1は本発明の一実施例である燃料の微粉炭を燃焼させる微粉炭焚きボイラであり 、パーナ 2と、水を噴霧する噴霧ノズル 6を有して燃焼用空気を供給するァフタエアポ ート 3とを火炉 1の壁面に備えた微粉炭焚きボイラ 100の構成のボイラ系統図を示し ている。  FIG. 1 is a pulverized coal-fired boiler that burns pulverized coal as a fuel according to an embodiment of the present invention, and has a burner 2 and a spray nozzle 6 that has a spray nozzle 6 that sprays water and supplies combustion air. A boiler system diagram of a pulverized coal fired boiler 100 equipped with a furnace 3 on the wall of the furnace 1 is shown.
[0022] 図 1の実施例の微粉炭焚きボイラ 100ではァフタエアポート 3に一流体ノズルの噴 霧ノズル 6を配設した場合を示して!/、る。  In the pulverized coal-fired boiler 100 of the embodiment of FIG. 1, the case where the spray nozzle 6 of the one-fluid nozzle is disposed in the after-air port 3 is shown.
[0023] 図 1において、微粉炭焚きボイラ 100は火炉 1を有し、火炉 1の壁面には燃料の微 粉炭と、燃焼用空気をこの微粉炭と混合して燃料ガスとして供給する複数のパーナ 2 が備えられている。 In FIG. 1, a pulverized coal-fired boiler 100 has a furnace 1, and a pulverized coal of fuel is provided on the wall of the furnace 1, and a plurality of burners that mix combustion air with the pulverized coal and supply as fuel gas. 2 is provided.
[0024] パーナ 2では燃焼用空気を燃料の微粉炭が完全燃焼するために必要な理論空気 比以下となる量の空気量を微粉炭と共に火炉 1の内部に燃料ガスとして供給して、火 炉の内部で空気不足の状態で燃料ガスを燃焼させて還元雰囲気とし、燃料ガスの燃 焼時に発生する NOxを窒素に還元して NOx生成を抑えている。 [0024] In Pana 2, the theoretical air necessary for the combustion of pulverized coal as fuel completely burns the combustion air. The amount of air below the ratio is supplied as fuel gas into the furnace 1 together with pulverized coal, and the fuel gas is combusted in a reducing atmosphere by air shortage inside the furnace. The generated NOx is reduced to nitrogen to suppress NOx generation.
[0025] パーナ 2が設置された位置より下流側となる位置の火炉 1の壁面には複数のァフタ エアポート 3が備えられて!/、る。  [0025] A plurality of after airports 3 are provided on the wall surface of the furnace 1 at a position downstream of the position where the PANA 2 is installed.
[0026] 還元雰囲気で酸素不足によってパーナ 2から火炉 1の内部に供給された燃料ガス のうち、この還元雰囲気で燃焼しなかった未燃ガス 10a及び発生した COを完全燃焼 させるために、ァフタエアポート 3からは理論空気比の不足分となる空気量より若干多 めの燃焼用空気を火炉 1の内部に供給して未燃ガス 1 Oa中の微粉炭及び COを燃焼 させ、 NOx及び COの生成を低減させている。  [0026] Of the fuel gas supplied from the burner 2 to the furnace 1 due to the lack of oxygen in the reducing atmosphere, the unburned gas 10a that was not burned in the reducing atmosphere and the generated CO were completely burned. From Airport 3, a slightly larger amount of combustion air than the theoretical air ratio is supplied to the inside of furnace 1 to burn pulverized coal and CO in unburned gas 1 Oa. The production is reduced.
[0027] 微粉炭焚きボイラ 100の燃料となる石炭は複数設置された微粉炭製造装置 7で微 粉に粉砕されて微粉炭となって配管 7bを通じてパーナ 2に夫々供給され、ブロア 12 力、らダクト配管 4を通じて供給された燃焼用空気とこの微粉炭とを共にこのパーナ 2か ら火炉 1の内部に燃料ガスとして投入して燃焼させる。  [0027] Coal as the fuel for the pulverized coal-fired boiler 100 is pulverized into fine powder by a plurality of installed pulverized coal production devices 7 to be supplied to the PANA 2 through the pipe 7b, respectively. The combustion air supplied through the duct pipe 4 and the pulverized coal are both injected into the furnace 1 from the burner 2 as fuel gas and burned.
[0028] パーナ 2から火炉 1の内部に投入された燃料ガスのうち、未燃となった未燃ガス 10a を燃焼させるための燃焼用空気は、ブロア 12によって外部から導いて熱交換器 13に て火炉 1から排出される高温排ガス 11と熱交換させることによって約 300°Cの高温空 気とし、ダクト配管 14を通じてァフタエアポート 3に燃焼用空気として供給する。  [0028] Combustion air for burning the unburned unburned gas 10a out of the fuel gas introduced into the furnace 1 from the burner 2 is guided from the outside by the blower 12 to the heat exchanger 13. Then, heat is exchanged with the high-temperature exhaust gas 11 discharged from the furnace 1 to obtain a high-temperature air of about 300 ° C and supplied to the after-air port 3 through the duct pipe 14 as combustion air.
[0029] 熱交換された高温空気の一部は、ダクト配管 14の途中に設けたダンバ 8によって流 量配分を調整され、火炉 1の壁面に設置されてパーナ 2をその内部に収容するウィン ドボックス 4に送給され、ウィンドボックス 4からパーナ 2の外周空気として火炉 1の内 部に投入される。  [0029] A part of the heat-exchanged high-temperature air is adjusted in flow distribution by a damper 8 provided in the middle of the duct pipe 14, and is installed on the wall surface of the furnace 1 to accommodate the parner 2 in the window. It is fed to box 4 and is put into the inside of furnace 1 from window box 4 as the outer air of PANA2.
[0030] また高温空気の一部は、ダンバ 9によって流量配分を調整され、火炉 1の壁面に設 置されてァフタエアポート 3をその内部に収容するウィンドボックス 5に導入され、この ウィンドボックス 5から前述したようにァフタエアポート 3を通じて火炉 1の内部に燃焼 用空気として投入される。  [0030] Further, a part of the high-temperature air is flow-distributed by the damper 9 and is introduced to the window box 5 which is installed on the wall surface of the furnace 1 and accommodates the after-air port 3 therein. As described above, the combustion air is fed into the furnace 1 through the after-air port 3.
[0031] そして火炉 1の内部で燃料の微粉炭が燃焼して生じた燃焼ガス 10は火炉 1の内部 を下流側に流下し、火炉 1の外部に排ガス 11となって配管 14bを通じて排出される。 配管 14bの途中には熱交換器 13が設置されており、排ガス 11は熱交換器 13にて燃 焼用空気と熱交換した後に脱硝、脱硫（図示せず）の処理を行い、配管 14bが連通 している煙突 15から大気へ放出される。 [0031] Then, the combustion gas 10 generated by burning the pulverized coal of the fuel inside the furnace 1 flows down the inside of the furnace 1 to the downstream side, becomes exhaust gas 11 outside the furnace 1, and is discharged through the pipe 14b. . A heat exchanger 13 is installed in the middle of the pipe 14b. The exhaust gas 11 is subjected to heat treatment with the combustion air in the heat exchanger 13 and then subjected to denitration and desulfurization (not shown). Released from the communicating chimney 15 to the atmosphere.
[0032] 火炉 1の壁面に設置したァフタエアポート 3の内部には噴霧ノズル 6が設置されて おり、燃料ガスが燃焼する際に発生するサーマル NOxの生成を抑制する冷却流体 である水 18をポンプ 16から配管 42を通じて噴霧ノズル 6に供給する。  [0032] A spray nozzle 6 is installed inside the after-air port 3 installed on the wall surface of the furnace 1, and water 18 that is a cooling fluid that suppresses the generation of thermal NOx generated when the fuel gas burns is supplied. Supply from the pump 16 to the spray nozzle 6 through the pipe 42.
[0033] 噴霧ノズル 6から火炉 1の内部に噴霧する冷却流体の水 18の流量は、火炉 1から 排ガス 11を外部に排出する配管 14bに配設された NOx検出器 55によって検出され る排ガス 11の NOx濃度に基づ!/、て調節できるように構成されて!/、る。  [0033] The flow rate of the cooling fluid water 18 sprayed from the spray nozzle 6 to the inside of the furnace 1 is the exhaust gas 11 detected by the NOx detector 55 disposed in the pipe 14b for discharging the exhaust gas 11 from the furnace 1 to the outside. Based on NOx concentration! /, Configured to be adjustable!
[0034] 即ち、 NOx検出器 55で検出された排ガス 11の NOx濃度信号は制御装置 50に入 力され、この制御装置 50では設定された所望の NOX設定値と NOx濃度信号とを比 較して排ガス 11の NOx濃度が所望の設定値を維持するように火炉 1の内部に噴霧 ノズル 6から噴霧すべき冷却流体の流量指令信号を演算し、制御装置 50からこの指 令信号を冷却流体の水 18を噴霧ノズル 6に供給する配管 42に設けた流量調整用の バルブ 17に出力するように構成されて!/、る。  That is, the NOx concentration signal of the exhaust gas 11 detected by the NOx detector 55 is input to the control device 50, and the control device 50 compares the set desired NOX set value with the NOx concentration signal. The flow rate command signal of the cooling fluid to be sprayed from the spray nozzle 6 is calculated inside the furnace 1 so that the NOx concentration of the exhaust gas 11 maintains the desired set value, and this command signal is sent from the control device 50 to the cooling fluid. It is configured to output to the flow rate adjusting valve 17 provided in the pipe 42 for supplying water 18 to the spray nozzle 6.
[0035] そして NOx検出器 55で検出した排ガス 11の NOx値が所望の設定値より高い場合 は、制御装置 50で演算した流量指令信号を受けてバルブ 17の開度を開けて噴霧ノ ズル 6から噴霧する冷却流体の水 18の流量を増大し、火炎温度の上昇を抑えて NO Xを低減する。  [0035] If the NOx value of the exhaust gas 11 detected by the NOx detector 55 is higher than the desired set value, the opening of the valve 17 is received in response to the flow command signal calculated by the control device 50, and the spray nozzle 6 Increase the flow rate of the cooling fluid water 18 sprayed from to suppress the rise in flame temperature and reduce NOx.
[0036] また、 NOx検出器 55で検出した排ガス 11の NOx値が所望の設定値より低い場合 は、制御装置 50で演算した流量指令信号を受けてバルブ 17の開度を操作して冷却 流体の水 18の流量を少なくする、もしくは供給を停止することで噴霧ノズル 6から噴 霧する噴霧水量を適正化し、効率の良い運転を行う。  [0036] If the NOx value of the exhaust gas 11 detected by the NOx detector 55 is lower than the desired set value, the flow rate command signal calculated by the control device 50 is received and the opening of the valve 17 is operated to cool the cooling fluid. By reducing the flow rate of water 18 or stopping the supply, the amount of water sprayed from the spray nozzle 6 is optimized, and efficient operation is performed.
[0037] また、排ガス 11の NOx濃度に対応させるだけでなぐ微粉炭焚きボイラ 100の負荷 に応じて噴霧ノズル 6から火炉 1の内部に噴霧する冷却流体の水 18の流量を制御す るようにしても良い。  [0037] Further, the flow rate of the cooling fluid water 18 sprayed from the spray nozzle 6 to the inside of the furnace 1 is controlled according to the load of the pulverized coal-fired boiler 100 just corresponding to the NOx concentration of the exhaust gas 11. May be.
[0038] この場合、微粉炭焚きボイラ 100の負荷は、制御室から指示されるボイラ負荷信号 に基づいて噴霧ノズル 6から火炉 1の内部に噴霧する冷却流体の水 18の流量を調 節できるように構成する。 [0038] In this case, the load of the pulverized coal fired boiler 100 adjusts the flow rate of the cooling fluid water 18 sprayed from the spray nozzle 6 into the furnace 1 based on the boiler load signal instructed from the control room. Configure to be able to save.
[0039] 即ち、制御室から指示されるボイラ負荷信号は制御装置 50に入力され、この制御 装置 50ではボイラ負荷に対応して火炉 1の内部に噴霧ノズル 6から噴霧すべき冷却 流体の流量指令信号を演算し、制御装置 50からこの指令信号を冷却流体を噴霧ノ ズル 6供給する配管 42に設けた流量調整用のバルブ 17に出力して冷却流体の流 量を調節するように成されて!/、る。  That is, the boiler load signal instructed from the control room is input to the control device 50, and the control device 50 commands the flow rate of the cooling fluid to be sprayed from the spray nozzle 6 in the furnace 1 in response to the boiler load. The controller 50 calculates the flow rate of the cooling fluid by outputting the command signal from the control device 50 to the flow rate adjusting valve 17 provided in the piping 42 for supplying the cooling fluid to the spray nozzle 6. ! /
[0040] そして、微粉炭焚きボイラ 100の負荷が低負荷時は冷却流体の水 18の流量を低流 量に、高負荷時には水 18の流量を高流量となるようにバルブ 17の開度を操作して噴 霧ノズル 6から噴霧する水 18の流量を調節することで噴霧する冷却流体の流量を適 正化しさらに高効率の運転が可能となる。  [0040] Then, when the load of the pulverized coal-fired boiler 100 is low, the opening of the valve 17 is set so that the flow rate of the cooling fluid water 18 is low and the flow rate of the water 18 is high when the load is high. By operating and adjusting the flow rate of the water 18 sprayed from the spray nozzle 6, the flow rate of the cooling fluid to be sprayed can be optimized and more efficient operation can be achieved.
[0041] 噴霧ノズル 6から噴霧すべき冷却流体の流量指令信号を演算し、流量調整用のバ ルブ 17に弁開度の指令信号を出力して冷却流体の流量を調節する制御装置 50の 構成を説明すると、図 15に制御装置 50のブロック図を示したように、制御装置 50に はボイラ負荷信号及び、 NOx検出器 55で検出した排ガス 11の NOx検出値が入力 される噴霧流量演算器 53を備えてレ、る。  [0041] Configuration of the control device 50 that calculates the flow rate command signal of the cooling fluid to be sprayed from the spray nozzle 6 and outputs the valve opening command signal to the flow rate adjustment valve 17 to adjust the flow rate of the cooling fluid As shown in the block diagram of the control device 50 in FIG. 15, the spray flow rate calculator to which the boiler load signal and the NOx detection value of the exhaust gas 11 detected by the NOx detector 55 are input to the control device 50. I have 53.
[0042] 制御装置 50にはボイラの運転負荷を設定するボイラ負荷設定器 51及び NOx濃度 を設定する NOx濃度設定器 52も備えられて!/、る。  [0042] The control device 50 is also provided with a boiler load setting device 51 for setting the operation load of the boiler and a NOx concentration setting device 52 for setting the NOx concentration!
[0043] そして、制御装置 50の噴霧流量演算器 53では、ボイラ負荷信号とボイラ負荷設定 器 51の負荷設定値 (しきい値)とを比較し、検出値が設定値を超えた場合に噴霧流 量演算器 52から設定値と検出値との差に対応した冷却流体の水 18の噴霧量を演算 して、この噴霧量に対応したバルブ 17の開度を指令信号としてバルブ 17に出力して 噴霧ノズル 6力も火炉 1の内部に噴霧する水 18の流量を調節するように構成されて いる。  [0043] Then, the spray flow rate calculator 53 of the control device 50 compares the boiler load signal with the load set value (threshold value) of the boiler load setter 51, and when the detected value exceeds the set value, The flow rate calculator 52 calculates the spray amount of the cooling fluid water 18 corresponding to the difference between the set value and the detected value, and outputs the opening degree of the valve 17 corresponding to this spray amount to the valve 17 as a command signal. The spray nozzle 6 force is also configured to adjust the flow rate of water 18 sprayed into the furnace 1.
[0044] 同様に、制御装置 50の噴霧流量演算器 53では、 NOx検出器 55で検出した排ガ ス 11の NOx検出信号と NOx濃度設定器 52の NOx設定値（しき!/、値）とを比較し、 検出値が設定値を超えた場合に噴霧流量演算器 53から設定値と検出値との差に対 応した冷却流体の水 18の噴霧量を演算して、この噴霧量に対応したバルブ 17の開 度を指令信号としてバルブ 17に出力して噴霧ノズル 6から火炉 1の内部に噴霧する 水 18の流量を調節するように構成されている。 Similarly, in the spray flow rate calculator 53 of the control device 50, the NOx detection signal of the exhaust gas 11 detected by the NOx detector 55 and the NOx set value (threshold! /, Value) of the NOx concentration setter 52 When the detected value exceeds the set value, the spray flow rate calculator 53 calculates the spray amount of the cooling fluid water 18 corresponding to the difference between the set value and the detected value, and responds to this spray amount. As a command signal, the valve 17 is output to the valve 17 and sprayed from the spray nozzle 6 into the furnace 1. It is configured to regulate the flow rate of water 18.
[0045] この制御装置 50によって操作され噴霧する水 18の流量を調節するバルブ 17の開 度操作状況を説明すると、図 16は冷却流体を調整するバルブを制御する特性図を 示すものであり、図 16の（A)の縦軸は排ガス 11の NOx検出濃度を、横軸はバルブ 1 7の開度を、破線は設定値を、実線は NOx検出濃度に対するバルブ 17の開度の特 性を夫々示している。 [0045] The opening operation state of the valve 17 that adjusts the flow rate of the sprayed water 18 that is operated by the control device 50 will be described. FIG. 16 is a characteristic diagram that controls the valve that adjusts the cooling fluid. The vertical axis of Fig. 16 (A) shows the NOx detection concentration of exhaust gas 11, the horizontal axis shows the opening degree of valve 17, the broken line shows the set value, and the solid line shows the characteristic of opening degree of valve 17 with respect to the NOx detection concentration. Each shows.
[0046] また、図 16の（B)の縦軸はボイラ負荷を、横軸はバルブ 17の開度を、破線は設定 値を、実線はボイラ負荷に対するバルブ 17の開度の特性を夫々示している。  [0046] In FIG. 16B, the vertical axis represents the boiler load, the horizontal axis represents the opening of the valve 17, the broken line represents the set value, and the solid line represents the characteristic of the opening of the valve 17 with respect to the boiler load. ing.
[0047] 図 16の (A)の特性図から理解できるように、制御装置 50による制御によって排ガス 11の NOx検出濃度の検出値が設定値 (たとえば NOx排出規制値)以下の場合は バルブ 17の開度を 0 (閉止）とし、噴霧ノズル 6から水の噴霧は行わない。 NOx検出 濃度の検出値が設定値より増大した場合は設定値との差に応じて演算した噴霧量に 対応したバルブ 17の開度に基づいてバルブ 17を開けて噴霧ノズル 6から水を噴霧 する制御を行う。図では NOx濃度とバルブ 17の開度は比例関係となっている力 こ の限りでない。  [0047] As can be understood from the characteristic diagram of FIG. 16A, when the detected value of the NOx detection concentration of the exhaust gas 11 is equal to or less than a set value (for example, the NOx emission regulation value) as controlled by the control device 50, the valve 17 The opening is set to 0 (closed) and water is not sprayed from the spray nozzle 6. NOx detection When the detected concentration value exceeds the set value, water is sprayed from the spray nozzle 6 by opening the valve 17 based on the opening of the valve 17 corresponding to the spray amount calculated according to the difference from the set value. Take control. In the figure, the NOx concentration and the opening degree of the valve 17 are not limited to this force.
[0048] 同様に図 16の（B)の特性図から理解できるように、制御装置 50による制御によつ てボイラ負荷が低負荷時には NOx排出量が元々少ないためバルブ 17の開度を 0 ( 閉止）とし、噴霧ノズル 6から水の噴霧は行わない。ボイラ負荷が上昇して定格負荷 に近づくにつれて NOx排出量も増大するため、ボイラ負荷の増加に伴い設定値との 差に応じて演算した噴霧量に対応したバルブ 17の開度に基づいてバルブ 17を開け て噴霧ノズル 6から水を噴霧する制御を行う。図では NOx濃度とバルブ 17の開度は 比例関係となってレ、る力 この限りでなレ、。  Similarly, as can be understood from the characteristic diagram of FIG. 16B, when the boiler load is low, the NOx emission amount is originally small when the boiler load is low, and therefore the opening degree of the valve 17 is set to 0 ( Do not spray water from the spray nozzle 6. As the boiler load increases and approaches the rated load, the NOx emissions also increase. Therefore, as the boiler load increases, the valve 17 is based on the opening of the valve 17 corresponding to the spray amount calculated according to the difference from the set value. Open and control to spray water from the spray nozzle 6. In the figure, the NOx concentration and the opening of the valve 17 are proportional to each other.
[0049] また、ボイラ負荷が高負荷時でも排ガスの NOx濃度が図 16の (A)の設定値 (排出 基準値)以下であれば、噴霧ノズル 6から更に水を噴霧させて NOxを必要以上に低 減させる必要はない。  [0049] Further, even when the boiler load is high, if the NOx concentration of the exhaust gas is less than the set value (discharge standard value) of (A) in Fig. 16, water is further sprayed from the spray nozzle 6, and NOx is more than necessary. There is no need to reduce it.
[0050] よって制御装置 50による制御によってボイラ負荷が高負荷（定格近傍）で、且つ排 ガスの NOx濃度が高い場合に、噴霧ノズル 6から水を噴霧するようにすれば、ボイラ の高効率運転が可能となる。 [0051] 次に、本発明の一実施例の微粉炭焚きボイラに適用されるァフタエアポート 3につ いて詳細に説明する。 [0050] Therefore, when the boiler load is high (near the rating) and the NOx concentration of the exhaust gas is high by the control by the control device 50, if the water is sprayed from the spray nozzle 6, high efficiency operation of the boiler is achieved. Is possible. [0051] Next, the after-air port 3 applied to the pulverized coal fired boiler of one embodiment of the present invention will be described in detail.
[0052] 図 2は図 1に示した本発明の一実施例の微粉炭焚きボイラに適用される噴霧ノズノレ を備えたァフタエアポート 3を拡大したァフタエアポートの部分構造図を示す。図 2に おいて、本実施例のァフタエアポート 3には、一端がウィンドボックス 5に設置され、他 端が火炉 1の壁面に開口したァフタエアポート 3の開口部 3aに面した円筒状の直進 流路 30が備えられている。  FIG. 2 is a partial structural diagram of the after air port in which the after air port 3 provided with the spray nozzle is applied to the pulverized coal burning boiler according to the embodiment of the present invention shown in FIG. In FIG. 2, the after-air port 3 of this embodiment has a cylindrical shape facing one opening 3a of the after-air port 3 whose one end is installed in the wind box 5 and whose other end is open on the wall surface of the furnace 1. A straight passage 30 is provided.
[0053] ァフタエアポート 3には、この直進流路 30の外周側に円錐台状の旋回流路 31が備 えられており、旋回流路 31の端部は火炉 1の壁面と接続してァフタエアポート 3の開 口部 3aの外縁を形成して!/、る。  The after-air port 3 is provided with a frustoconical swirl passage 31 on the outer peripheral side of the straight passage 30, and the end of the swirl passage 31 is connected to the wall surface of the furnace 1. Form the outer edge of the opening 3a of the after-air port 3!
[0054] そして、燃焼用空気の一部である直進流 35は直進流路 30の胴部に形成した穴部 力も直進流路 30の内部に導かれ、この直進流路 30の先端の開口力も火炉 1の内部 に供給される。  [0054] The straight flow 35, which is a part of the combustion air, is also introduced into the straight flow channel 30 by the hole force formed in the trunk of the straight flow channel 30, and the opening force at the tip of the straight flow channel 30 is also generated. Supplied inside furnace 1.
[0055] また、燃焼用空気の一部である旋回流 36は直進流路 30の外周側に設置された円 錐台状の旋回流路 31に設けたレジスタ 32で旋回強度を調整されて旋回流路 31の 先端の開口力 火炉 1の内部に供給される。  [0055] Further, the swirl flow 36, which is a part of the combustion air, is swirled with the swirl strength adjusted by the register 32 provided in the frustum-shaped swirl flow path 31 provided on the outer peripheral side of the straight flow path 30. Opening force at the tip of the flow path 31 Supplied into the furnace 1.
[0056] 直進流路 30の胴部に形成した穴部の外側には可動式のダンバ 33が配設され、旋 回流路 31の上流側にも可動式のダンバ 34が配設されており、これらのダンバ 33、 3 4を稼動させることにより直進流路 30及び旋回流路 31を流下する燃焼用空気の流量 配分を調整する。  [0056] A movable damper 33 is disposed outside the hole formed in the trunk portion of the straight flow path 30, and a movable damper 34 is also disposed on the upstream side of the turning flow path 31, By operating these dampers 33 and 3 4, the flow distribution of the combustion air flowing down the straight flow path 30 and the swirl flow path 31 is adjusted.
[0057] ァフタエアポート 3に備えられた円筒状の直進流路 30の先端の噴出口に噴霧ノズ ル 6を設置している。そして、噴霧ノズル 6の先端がァフタエアポート 3の開口部 3aの 近傍に位置するように直進流路 30の軸心に沿って噴霧ノズル 6を配設し、冷却流体 である水 18を噴霧ノズル 6の先端から NOx生成を抑制するように火炉 1の内部に噴 る。  [0057] The spray nozzle 6 is installed at the jet outlet at the tip of the cylindrical straight passage 30 provided in the after-air port 3. Then, the spray nozzle 6 is disposed along the axis of the straight passage 30 so that the tip of the spray nozzle 6 is positioned in the vicinity of the opening 3a of the after-air port 3, and water 18 that is a cooling fluid is sprayed to the spray nozzle. It is injected into the furnace 1 from the tip of 6 to suppress NOx generation.
[0058] 噴霧ノズル 6から冷却流体の水 18を火炉 1の内部に噴霧することによる NOx生成 の抑制作用を以下に説明する。  [0058] The action of suppressing NOx generation by spraying the cooling fluid water 18 from the spray nozzle 6 into the furnace 1 will be described below.
[0059] ァフタエアポート 3の開口部 3aに面した火炉 1の内部にはァフタエアポート 3に備え られた直進流路 30及び旋回流路 31から夫々供給される燃焼用空気によって図 2に 示したように開口部 3aから火炉 1の中心側に向かって広がる燃焼用空気の噴流 40 が形成される。 [0059] In the furnace 1 facing the opening 3a of the after-air port 3, the after-air port 3 is provided. As shown in FIG. 2, a combustion air jet 40 spreading from the opening 3a toward the center of the furnace 1 is formed by the combustion air supplied from the straight flow path 30 and the swirl flow path 31 respectively. .
[0060] ァフタエアポート 3の開口部 3aを通じて直進流路 30及び旋回流路 31から火炉 1の 内部に供給された燃焼用空気の噴流 40は、火炉 1の内部をパーナ 2の位置から燃 焼ガス 10と共に下流側のァフタエアポート 3の位置に流下してくる未燃の微粉炭を含 んだ未燃ガス 1 Oaと混合する混合領域 41を燃焼用空気の噴流 40の外側縁部に形 成する。  [0060] The jet 40 of combustion air supplied from the straight passage 30 and the swirl passage 31 to the inside of the furnace 1 through the opening 3a of the after-air port 3 burns the inside of the furnace 1 from the position of the burner 2. A mixing area 41 mixed with unburned gas 1 Oa containing unburned pulverized coal flowing down to the position of downstream air port 3 together with gas 10 is formed at the outer edge of combustion air jet 40 To do.
[0061] この混合領域 41では噴流 40として供給される燃焼用空気と未燃ガス 10aとを混合 することによって未燃ガス 10aが燃焼し、形成される火炎の温度が上昇してサーマル NOxが生成する。  [0061] In the mixing region 41, the combustion air supplied as the jet 40 and the unburned gas 10a are mixed to burn the unburned gas 10a, and the temperature of the formed flame rises to generate thermal NOx. To do.
[0062] サーマル NOxは燃焼時の火炎温度で一義的にその生成量が決まり、約 1700K以 上で生成が始まる。サーマル NOxの生成量は火炎温度の上昇に対して約 2乗の感 度であり、高温になるほど生成量も大幅に増大する  [0062] The amount of thermal NOx produced is uniquely determined by the flame temperature during combustion, and production begins at about 1700K or higher. The amount of thermal NOx produced is about a square of the rise in flame temperature, and the amount produced increases significantly as the temperature rises.
そこで、本実施例ではァフタエアポート 3の開口部 3aの近傍に配設した噴霧ノズノレ 6から配管 42を通じて導かれた冷却流体の水 18をこの混合領域 41と重なるような噴 霧範囲 18aに噴霧することによって、混合領域 41と重なる噴霧範囲 18aに噴霧され た水 18の持つ水の潜熱、顕熱によって混合領域 41で未燃ガス 10aが燃焼する火炎 の温度の熱を奪レ、火炎温度の上昇を抑制するので、最もサーマル NOxが生成し易 い混合領域 41でのサーマル NOxの生成が減少できる。  Therefore, in this embodiment, the cooling fluid water 18 introduced through the pipe 42 from the spray nozzle 6 disposed in the vicinity of the opening 3a of the after-air port 3 is sprayed to the spray area 18a so as to overlap the mixing area 41. As a result, the latent heat of the water 18 sprayed in the spray area 18a that overlaps the mixing area 41, and the temperature of the flame in which the unburned gas 10a burns in the mixing area 41 due to sensible heat, are removed. Since the increase is suppressed, the generation of thermal NOx in the mixing region 41 where the thermal NOx is most easily generated can be reduced.
[0063] 本実施例によれば、混合領域 41と重なる噴霧範囲 18aに噴霧ノズル 6から的確に 水 18を噴霧できるので、混合領域 41にて燃焼する未燃ガス 10aの火炎温度を約 16 00K以下に、好ましくは約 1600K〜約 1400Kに抑制することが可能となり、よって ボイラで生成されるサーマル NOxの濃度を約 10〜30%低減することが出来る。  [0063] According to the present embodiment, since the water 18 can be accurately sprayed from the spray nozzle 6 to the spray range 18a overlapping with the mixing region 41, the flame temperature of the unburned gas 10a combusted in the mixing region 41 is about 1600 K. In the following, it becomes possible to suppress the temperature preferably to about 1600K to about 1400K, so that the concentration of thermal NOx generated in the boiler can be reduced by about 10 to 30%.
[0064] また、本実施例の噴霧ノズル 6はァフタエアポート 3の開口部 3aの近傍に配設され ているので、噴霧ノズルへの灰付着や、高温の燃焼ガスとの接触による構造材の変 形が回避でき、よって長期間の使用に耐えられる信頼性の高!/、噴霧ノズルを得ること が可能となる。 [0065] ところで、噴霧ノズル 6から火炉 1の内部に形成される混合領域 41に向けて噴霧範 囲 18aに噴霧する冷却流体の水 18は、ァフタエアポート 3から供給される燃焼用空 気の噴流 40の広がりと形状に合わせて未燃ガス 10aと混合する混合領域 41と重なる 噴霧範囲 18aに的確に噴霧できるように、噴霧ノズル 6が回転、及び軸方向の前後に 移動できる構造としても良い。 [0064] In addition, since the spray nozzle 6 of the present embodiment is disposed in the vicinity of the opening 3a of the after-air port 3, ash adhesion to the spray nozzle or the contact of the structural material due to contact with high-temperature combustion gas. Deformation can be avoided, so that it is possible to obtain a highly reliable spray nozzle that can withstand long-term use. [0065] By the way, the cooling fluid water 18 sprayed to the spray range 18a from the spray nozzle 6 toward the mixing region 41 formed inside the furnace 1 is the combustion air supplied from the after air port 3. The spray nozzle 6 may be rotated and moved back and forth in the axial direction so that it can be sprayed accurately in the spray area 18a that overlaps with the mixing area 41 mixed with the unburned gas 10a according to the spread and shape of the jet 40 .
[0066] 図 3は図 2の A— A矢視図である噴霧ノズルを備えたァフタエアポート 3の開口部 3a を示す。図 3において、冷却流体の水 18を図 2に示したァフタエアポート 3の開口部 3 aから供給される燃焼用空気の噴流 40と未燃ガス 10aとの混合領域 41と重なる噴霧 範囲 18aの一形態として噴霧ノズル 6から同心円状に広がるように噴霧する場合を示 している。  FIG. 3 shows an opening 3a of the after-air port 3 provided with a spray nozzle as seen from the arrows AA in FIG. In FIG. 3, the water 18 of the cooling fluid is sprayed in the spray range 18a that overlaps the mixing region 41 of the jet 40 of combustion air supplied from the opening 3a of the after air port 3 shown in FIG. 2 and the unburned gas 10a. As a form, the spray nozzle 6 sprays so as to spread concentrically.
[0067] また、噴霧ノズル 6の先端の形状を変えて図 3に示した噴霧パターンと異なるような 図 4に示したような噴霧範囲 18aの一形態として水 18をコーン状に噴霧するようにし ても、 NOx生成部位である燃焼用空気の噴流 40と未燃ガス 10aとの混合領域 41と 重なる噴霧範囲 18aに冷却流体の水 18の水分が供給できるので同様の効果が得ら れる。  [0067] Further, the shape of the tip of the spray nozzle 6 is changed to be different from the spray pattern shown in FIG. 3, and water 18 is sprayed in a cone shape as one form of the spray range 18a as shown in FIG. However, since the moisture of the cooling fluid water 18 can be supplied to the spray range 18a that overlaps the mixing region 41 of the combustion air jet 40 and the unburned gas 10a, which is the NOx generation site, the same effect can be obtained.
[0068] 上記した本発明の実施例によれば、ァフタエアポートからの燃焼用空気の供給で 火炉内部で未燃ガスが燃焼する際に生じる火炎温度の上昇を確実に抑制し、燃焼 時に発生するサーマル NOxの濃度を低減する信頼性の高い微粉炭焚きボイラを実 現することが出来る。  [0068] According to the above-described embodiment of the present invention, the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and occurs during combustion. This makes it possible to realize a highly reliable pulverized coal fired boiler that reduces the concentration of thermal NOx.
実施例 2  Example 2
[0069] 次に図 5及び図 6には、図 1に示した本発明の一実施例である微粉炭焚きボイラに 採用するァフタエアポートの他の構造である実施例の部分構造図を示す。  Next, FIG. 5 and FIG. 6 show partial structural views of an embodiment which is another structure of the after-air port employed in the pulverized coal burning boiler which is an embodiment of the present invention shown in FIG. .
[0070] 図 5は噴霧ノズルを備えたァフタエアポートの他の実施例の構造を、図 6は図 5の B  [0070] FIG. 5 shows the structure of another embodiment of the after-air port provided with the spray nozzle, and FIG.
B矢視図を示しており、本実施例のァフタエアポート 3が採用される微粉炭焚きボイ ラの構成は図 1に示した実施例の微粉炭焚きボイラ 100と同じ構成であるので説明は 省略する。  As shown in the arrow B, the configuration of the pulverized coal fired boiler adopting the after-airport 3 of this embodiment is the same as that of the pulverized coal fired boiler 100 of the embodiment shown in FIG. Omitted.
[0071] また、図 5及び図 6に示す本実施例のァフタエアポート 3の構造は、図 2乃至図 4に 示したァフタエアポート 3の実施例と基本構成は共通であるので共通の構成につい てはその説明を省略し、相違する部分についてのみ説明する。 Further, the structure of the after-air port 3 of this embodiment shown in FIGS. 5 and 6 is the same as that of the embodiment of the after-air port 3 shown in FIGS. Last Therefore, the description thereof is omitted, and only different portions will be described.
[0072] 図 5及び図 6において、微粉炭焚きボイラに採用される噴霧ノズルを備えた本実施 例のァフタエアポート 3では、冷却流体の水 18を噴霧する噴霧ノズル 6を直進流路 3 0の外周側となる旋回流路 31の開口部に複数個配置した構成である。そして噴霧ノ ズル 6の先端がァフタエアポート 3の開口部 3aの近傍に位置するように配設されてい るのは図 2の実施例に示したァフタエアポート 3の構成と同じである。  In FIG. 5 and FIG. 6, in the after-air port 3 of this embodiment provided with the spray nozzle employed in the pulverized coal-fired boiler, the spray nozzle 6 for spraying the cooling fluid water 18 is connected to the straight flow path 30. A plurality of openings are arranged in the opening of the swirl flow path 31 on the outer peripheral side. The tip of the spray nozzle 6 is disposed so as to be positioned in the vicinity of the opening 3a of the after air port 3 as in the configuration of the after air port 3 shown in the embodiment of FIG.
[0073] そして本実施例のァフタエアポート 3においても、ァフタエアポート 3からァフタエア ポート 3の開口部 3aに面した火炉 1の内部に噴出する燃焼用空気の噴流 40と未燃 ガス 10aとが混合する混合領域 41に対して、噴霧ノズル 6から冷却流体の水 18をこ の混合領域 41と重なるような噴霧範囲 18aにより的確に噴霧することが出来る。  [0073] Also in the after air port 3 of this embodiment, the combustion air jet 40 and unburned gas 10a spouted from the after air port 3 into the furnace 1 facing the opening 3a of the after air port 3 Cooling fluid water 18 can be accurately sprayed from the spray nozzle 6 to the mixing region 41 to be mixed in the spraying region 18a so as to overlap the mixing region 41.
[0074] よって本実施例では、噴霧された水 18の持つ水の潜熱、顕熱によって混合領域 41 で未燃ガス 10aが燃焼する火炎の温度の熱を奪って火炎温度の上昇を約 1600K以 下に、好ましくは約 1600K〜約 1400Kに抑制することが可能となり、よってボイラで 生成されるサーマル NOxの濃度を約 10〜30%低減することが出来る。  Therefore, in this embodiment, the heat of the flame at which the unburned gas 10a burns in the mixing region 41 is deprived by the latent heat and sensible heat of the sprayed water 18 to increase the flame temperature by about 1600K or more. Below, it becomes possible to suppress to preferably about 1600K to about 1400K, so that the concentration of thermal NOx generated in the boiler can be reduced by about 10 to 30%.
[0075] また、本実施例の噴霧ノズル 6もァフタエアポート 3の開口部 3aの近傍に配設され ているので、噴霧ノズルへの灰付着や、高温の燃焼ガスとの接触による構造材の変 形が回避でき、長期間の使用に耐えられる信頼性の高い噴霧ノズルを得ることが可 能となる。また、噴霧ノズルを複数個配置していることから、一部の噴霧ノズルに目詰 まりが発生してもその他の噴霧ノズルによって必要な冷却流体の噴霧は維持できる ので、長期間の使用に耐えられる信頼性の高い噴霧ノズルを得ることが可能となる。 実施例 3  [0075] In addition, since the spray nozzle 6 of the present embodiment is also disposed in the vicinity of the opening 3a of the after-air port 3, ash adhesion to the spray nozzle or the contact of the structural material due to contact with high-temperature combustion gas It is possible to obtain a highly reliable spray nozzle that can avoid deformation and can withstand long-term use. In addition, since several spray nozzles are arranged, even if some of the spray nozzles are clogged, the spray of the necessary cooling fluid can be maintained by other spray nozzles, so it can withstand long-term use. It is possible to obtain a highly reliable spray nozzle. Example 3
[0076] 次に図 7及び図 8には、図 1に示した本発明の一実施例である微粉炭焚きボイラに 採用するァフタエアポートの更に他の実施例の部分構造図を示す。  Next, FIG. 7 and FIG. 8 show partial structural views of still another embodiment of the after-airport employed in the pulverized coal fired boiler which is an embodiment of the present invention shown in FIG.
[0077] 図 7は噴霧ノズルを備えたァフタエアポートの更に他の実施例の構造を、図 8は図 7 の C C矢視図を示しており、本実施例のァフタエアポート 3が採用される微粉炭焚 きボイラの構成は図 1に示した実施例の微粉炭焚きボイラ 100と同じ構成であるので 説明は省略する。  [0077] Fig. 7 shows the structure of still another embodiment of the after-air port provided with the spray nozzle, and Fig. 8 shows the CC arrow view of Fig. 7, and the after-air port 3 of this embodiment is adopted. The structure of the pulverized coal burning boiler is the same as that of the pulverized coal burning boiler 100 of the embodiment shown in FIG.
[0078] また、図 7及び図 8に示す本実施例のァフタエアポート 3の構造は、図 2乃至図 4に 示したァフタエアポート 3の実施例と基本構成は共通であるので共通の構成につい てはその説明を省略し、相違する部分について説明する。 Further, the structure of the after-air port 3 of this embodiment shown in FIGS. 7 and 8 is shown in FIGS. Since the basic configuration is the same as that of the embodiment of the after-air port 3 shown, the description of the common configuration will be omitted, and different portions will be described.
[0079] 図 7及び図 8において、微粉炭焚きボイラに採用される本実施例の噴霧ノズルを備 えたァフタエアポート 3では、冷却流体の水 18を噴霧する噴霧ノズル 6を直進流路 3 0の内側の開口部と、直進流路 30の外周側となる旋回流路 31の開口部に複数個、 夫々配置した構成である。そして各噴霧ノズル 6の先端がァフタエアポート 3の開口 部 3aの近傍に位置するように配設されているのは図 2の実施例に示したァフタエア ポート 3の構成と同じである。  In FIG. 7 and FIG. 8, in the after-air port 3 equipped with the spray nozzle of this embodiment employed in the pulverized coal burning boiler, the spray nozzle 6 for spraying the cooling fluid water 18 is connected to the straight flow path 30. And a plurality of openings are arranged in the opening of the swirl flow path 31 on the outer peripheral side of the straight flow path 30, respectively. The tip of each spray nozzle 6 is disposed in the vicinity of the opening 3a of the after air port 3 in the same manner as the after air port 3 shown in the embodiment of FIG.
[0080] そして本実施例のァフタエアポート 3においても、ァフタエアポート 3からァフタエア ポート 3の開口部 3aに面した火炉 1の内部に噴出する燃焼用空気の噴流 40と未燃 ガス 10aとが混合する混合領域 41に対して、複数の噴霧ノズル 6から冷却流体の水 1 8をこの混合領域 41と重なるような噴霧範囲 18aにより的確に、且つ均等に噴霧する ことが出来る。  [0080] Also in the after air port 3 of the present embodiment, the combustion air jet 40 and the unburned gas 10a are injected from the after air port 3 into the furnace 1 facing the opening 3a of the after air port 3. The cooling fluid water 18 can be sprayed from the plurality of spray nozzles 6 to the mixing region 41 to be mixed more precisely and evenly in the spraying region 18 a that overlaps the mixing region 41.
[0081] よって本実施例では、噴霧された水 18の持つ水の潜熱、顕熱によって混合領域 41 で未燃ガス 10aが燃焼する火炎の温度の熱を奪って火炎温度の上昇を約 1600K以 下に、好ましくは約 1600K〜約 1400Kに、より確実に抑制することが可能となり、よ つてボイラで生成されるサーマル NOxの濃度を約 10〜30%低減することが出来る。  Therefore, in this embodiment, the heat of the flame at which the unburned gas 10a burns in the mixing region 41 is taken away by the latent heat and sensible heat of the sprayed water 18 to increase the flame temperature by about 1600K or more. Below, it becomes possible to more reliably suppress to about 1600K to about 1400K, and the concentration of thermal NOx generated in the boiler can be reduced by about 10 to 30%.
[0082] また、本実施例の噴霧ノズル 6もァフタエアポート 3の開口部 3aの近傍に配設され ているので、噴霧ノズルへの灰付着や、高温の燃焼ガスとの接触による構造材の変 形が回避できる。また、噴霧ノズルを複数個配置していることから、一部の噴霧ノズル に目詰まりが発生してもその他の噴霧ノズルによって必要な冷却流体の噴霧は維持 できるので、長期間の使用に耐えられる信頼性の高!/、噴霧ノズルを得ることが可能と なる。  [0082] In addition, since the spray nozzle 6 of the present embodiment is also disposed in the vicinity of the opening 3a of the after-air port 3, ash adhesion to the spray nozzle or the contact of high-temperature combustion gas with the structural material Deformation can be avoided. In addition, since several spray nozzles are arranged, even if some of the spray nozzles are clogged, the spray of the required cooling fluid can be maintained by other spray nozzles, so it can withstand long-term use. Highly reliable! / It becomes possible to obtain a spray nozzle.
実施例 4  Example 4
[0083] 次に図 9及び図 10には、図 1に示した本発明の一実施例である微粉炭焚きボイラ に採用するァフタエアポートの別の実施例の部分構造図を示す。  [0083] Next, Figs. 9 and 10 are partial structural views of another embodiment of the after-airport employed in the pulverized coal fired boiler as an embodiment of the present invention shown in Fig. 1.
[0084] 図 9及び図 10は噴霧ノズルを備えたァフタエアポートの別の実施例の構造を夫々 示しており、本実施例のァフタエアポート 3が採用される微粉炭焚きボイラの構成は 図 1に示した実施例の微粉炭焚きボイラ 100と同じ構成であるので説明は省略する。 FIG. 9 and FIG. 10 show the structure of another embodiment of the after-air port provided with the spray nozzle, respectively, and the configuration of the pulverized coal fired boiler in which the after-air port 3 of this embodiment is adopted is as follows. Since it is the same structure as the pulverized coal burning boiler 100 of the Example shown in FIG. 1, description is abbreviate | omitted.
[0085] また、図 9及び図 10に示す本実施例のァフタエアポート 3の構造は、図 5及び図 6 に夫々示したァフタエアポート 3の各実施例と基本構成は共通であるので共通の構 成についてはその説明を省略し、相違する部分についてのみ説明する。 Further, the structure of the after-air port 3 of the present embodiment shown in FIGS. 9 and 10 is the same as each of the embodiments of the after-air port 3 shown in FIGS. The description of this configuration is omitted, and only the differences are described.
[0086] 図 9及び図 10において、各実施例のァフタエアポート 3に設置された冷却流体の 水 18を噴霧する噴霧ノズル 6は、噴霧ノズル 6の先端の位置をァフタエアポート 3の 開口部 3aからウィンドボックス 5の壁面寄りに位置するように配置させて火炉 1から遠 ざけた構成であり、噴霧ノズル 6の先端の位置はァフタエアポート 3aの開口部 3aより も燃焼用空気の噴流 40の上流側となるァフタエアポート 3aの内部の位置に配置され ている。 In FIG. 9 and FIG. 10, the spray nozzle 6 that sprays the cooling fluid water 18 installed in the after air port 3 of each embodiment has the position of the tip of the spray nozzle 6 as the opening of the after air port 3. It is arranged so that it is located closer to the wall of the wind box 5 from 3a and away from the furnace 1. The tip of the spray nozzle 6 is located at the tip of the after-air port 3a, and the jet of combustion air 40 It is arranged at the position inside the after-air port 3a on the upstream side of the.
[0087] 本実施例によれば、ァフタエアポート 3の開口部 3aから火炉 1の内部に供給される 燃焼用空気の噴流 40の上流位置で噴霧ノズル 6から冷却流体の水 18を噴霧して気 化させ、ァフタエアポート 3から供給する燃焼用空気の噴流 40にさらに均一に水分を 混合することで、ァフタエアポートから供給する燃焼用空気の噴流 40自体に水分が 添加するので、この噴流 40と未燃ガス 10aとが混合する混合領域 41と重なる噴霧領 域 41に水分をより確実に供給でき、火炎温度の上昇をより確実に抑制できるというメ ジ 卜力 fcる。  According to the present embodiment, the cooling fluid water 18 is sprayed from the spray nozzle 6 at the upstream position of the jet 40 of combustion air supplied into the furnace 1 from the opening 3 a of the after air port 3. The water is added to the combustion air jet 40 itself supplied from the after-air port by vaporizing and mixing water into the combustion air jet 40 supplied from the after-air port 3 more evenly. It is possible to supply moisture to the spraying region 41 that overlaps with the mixing region 41 where the unburned gas 10a and 40 are mixed, and to prevent the rise in the flame temperature more reliably.
[0088] また、本実施例のァフタエアポート 3に設置された噴霧ノズル 6は冷却流体として水 18を噴霧する一流体の噴霧ノズルを示した力 S、水 18と蒸気 20との冷却流体を噴霧 する二流体の噴霧ノズルにも適用できるものである。  In addition, the spray nozzle 6 installed in the after-air port 3 of the present embodiment has a force S indicating a spray nozzle for spraying water 18 as a cooling fluid, and the cooling fluid of water 18 and steam 20. It can also be applied to a two-fluid spray nozzle.
[0089] 尚、説明は省略したが、図 9及び図 10に夫々示した本実施例のァフタエアポート 3 に設置された噴霧ノズル 6による冷却流体の制御は、前述した各実施例と同様に制 御装置 50によって冷却流体の流量を調節することにより行われる。  Although explanation is omitted, the control of the cooling fluid by the spray nozzle 6 installed in the after air port 3 of the present embodiment shown in FIGS. 9 and 10 is the same as in each of the embodiments described above. This is done by adjusting the flow rate of the cooling fluid by the control device 50.
[0090] 上記した本発明の実施例によっても、ァフタエアポートからの燃焼用空気の供給で 火炉内部で未燃ガスが燃焼する際に生じる火炎温度の上昇を確実に抑制し、燃焼 時に発生するサーマル NOxの濃度を低減する信頼性の高い微粉炭焚きボイラを実 現することが出来る。  [0090] Also according to the above-described embodiment of the present invention, the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and occurs during combustion. A reliable pulverized coal fired boiler that reduces the concentration of thermal NOx can be realized.
実施例 5 [0091] 次に本発明の他の実施例である微粉炭焚きボイラについて図面を用いて説明する Example 5 Next, a pulverized coal fired boiler as another embodiment of the present invention will be described with reference to the drawings.
[0092] 図 11は燃料の微粉炭を燃焼させるパーナ 2と、水と蒸気との双方を噴霧する噴霧ノ ズル 6を有して燃焼用空気を供給するァフタエアポート 3とを火炉 1の壁面に備えた 本発明の他の実施例である微粉炭焚きボイラ 100の構成を示すボイラ系統図である [0092] FIG. 11 shows a wall surface of the furnace 1 that includes a burner 2 that burns pulverized coal as a fuel and a after-air port 3 that has a spray nozzle 6 that sprays both water and steam and supplies combustion air. It is the boiler system diagram which shows the structure of the pulverized coal burning boiler 100 which is the other Example of this invention prepared for
[0093] 本実施例の微粉炭焚きボイラの構成は図 1に示した実施例の微粉炭焚きボイラ 10 0と基本構成は共通であるので説明は省略し、相違する部分についてのみ説明する [0093] The configuration of the pulverized coal burning boiler of this embodiment is the same as that of the pulverized coal burning boiler 100 of the embodiment shown in FIG.
[0094] 図 11において、本実施例の微粉炭焚きボイラ 100では、ァフタエアポート 3に備え られた噴霧ノズル 6には水 18と蒸気 20との二流体を噴霧することが可能な二流体ノ ズノレを採用している。 In FIG. 11, in the pulverized coal burning boiler 100 of the present embodiment, the two-fluid nozzle capable of spraying two fluids of water 18 and steam 20 is applied to the spray nozzle 6 provided in the after-air port 3. Zunore is adopted.
[0095] 水 18と蒸気 20との二流体を冷却流体として噴霧する噴霧ノズル 6に水 18を供給す る系統は、図 1に示したものと同じ配管 42及びバルブ 17を備えた水の供給系統であ  [0095] The system for supplying water 18 to the spray nozzle 6 that sprays two fluids of water 18 and steam 20 as cooling fluid is the same as that shown in FIG. System
[0096] そして、二流体を噴霧する噴霧ノズル 6に蒸気 20を供給する蒸気の系統系統は、 発電所内で使用する蒸気の一部を導いて貯蔵して所定の圧力に設定する蒸気タン ク 21と、この蒸気タンク 21に貯蔵された蒸気 20を噴霧ノズル 6に供給する配管 43と を備えており、配管 43には供給する蒸気 20の蒸気量を調節するバルブ 22が設置さ れている。 [0096] A steam system that supplies steam 20 to the spray nozzle 6 that sprays two fluids is a steam tank that guides and stores part of the steam used in the power plant and sets it to a predetermined pressure. And a pipe 43 for supplying the steam 20 stored in the steam tank 21 to the spray nozzle 6, and a valve 22 for adjusting the amount of steam 20 to be supplied is installed in the pipe 43.
[0097] 二流体の噴霧ノズル 6から火炉 1の内部に噴霧する蒸気 20の蒸気量を調節するバ ルブ 22の開度は制御装置 50によって制御される力 水 18の噴霧量を調節するバル ブ 17の開度の制御と同様に、制御装置 50では NOx検出器 55で検出した排ガス 11 の NOx排出濃度と、ボイラ負荷とに応じて噴霧流量演算器 53にて NOx濃度設定器 52及びボイラ負荷設定器 51の各設定値とを比較して供給が必要な蒸気 20の蒸気 量を演算し、この蒸気量に対応したバルブ 22の開度を開度信号として制御装置 50 の噴霧流量演算器 53からバルブ 22に指令として噴霧ノズル 6から必要量の蒸気 20 の噴霧を行なっている。 [0098] 尚、二流体の噴霧ノズル 6から火炉 1の内部に噴霧する蒸気 20の噴霧状況は、図 2 乃至図 4の噴霧ノズル 6で示した混合領域 41に重ねられる噴霧範囲 18aと同様のも のである。 [0097] The opening degree of the valve 22 for adjusting the amount of steam 20 sprayed from the two-fluid spray nozzle 6 into the furnace 1 is controlled by the control device 50 The valve for adjusting the spray amount of water 18 Similarly to the control of the opening degree 17, the control device 50 uses the NOx concentration setter 52 and the boiler load in the spray flow rate calculator 53 according to the NOx emission concentration of the exhaust gas 11 detected by the NOx detector 55 and the boiler load. The amount of steam 20 that needs to be supplied is calculated by comparing each setting value of the setting device 51, and the opening of the valve 22 corresponding to this amount of steam is used as the opening signal to calculate the spray flow rate calculator 53 of the control device 50. Therefore, the required amount of steam 20 is sprayed from the spray nozzle 6 as a command to the valve 22. [0098] The state of spraying of the steam 20 sprayed from the two-fluid spray nozzle 6 into the furnace 1 is the same as the spray range 18a superimposed on the mixing region 41 shown by the spray nozzle 6 in Figs. It is.
[0099] また、制御装置 50によるバルブ 22の弁開度の制御は図 16の（A)及び図 16の（B) に示した制御装置 50によるバルブ 17の弁開度の制御に準じたものとなる。  [0099] Further, the control of the valve opening degree of the valve 22 by the control device 50 is based on the control of the valve opening degree of the valve 17 by the control device 50 shown in Fig. 16 (A) and Fig. 16 (B). It becomes.
[0100] 本実施例では上記のように構成しているので、水 18と蒸気 20との二流体を噴霧す る噴霧ノズル 6から噴霧される蒸気 20の流量が噴霧される水 18の流量変化に追随さ せること力 Sでさる。  [0100] Since the present embodiment is configured as described above, the flow rate of the steam 20 sprayed from the spray nozzle 6 spraying the two fluids of the water 18 and the steam 20 is changed in the flow rate of the water 18 to be sprayed. With the power S to follow.
[0101] したがって本実施例の二流体ノズルの噴霧ノズル 6を用いることで、火炉 1の内部に 噴霧される冷却流体の液滴がより微細になり、水分の蒸発が促進されるので、すば やく火炎温度の上昇を抑制できるというメリットがある。  [0101] Therefore, by using the spray nozzle 6 of the two-fluid nozzle of this embodiment, the droplets of the cooling fluid sprayed into the furnace 1 become finer and the evaporation of moisture is promoted. There is an advantage that the rise in flame temperature can be suppressed.
[0102] 上記した本発明の実施例によっても、ァフタエアポートからの燃焼用空気の供給に よって火炉内部で未燃ガスが燃焼する際に生じる火炎温度の上昇を確実に抑制し、 燃焼時に発生するサーマル NOxの濃度を低減する信頼性の高い微粉炭焚きボイラ を実現することが出来る。  [0102] Also according to the above-described embodiment of the present invention, the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and is generated during combustion. It is possible to realize a highly reliable pulverized coal fired boiler that reduces the concentration of thermal NOx.
実施例 6  Example 6
[0103] 次に本発明の更に他の実施例である微粉炭焚きボイラについて図面を用いて説明 する。  [0103] Next, a pulverized coal fired boiler as still another embodiment of the present invention will be described with reference to the drawings.
[0104] 図 12は燃料の微粉炭を燃焼させるパーナ 2と、燃焼用空気を供給するァフタエア ポート 3と、ァフタエアポート 3に冷却流体の水を噴霧する噴霧ノズル 6を配設した本 発明更に他の実施例である微粉炭焚きボイラ 100の構成を示すボイラ系統図である  FIG. 12 shows the present invention in which a burner 2 for burning pulverized coal of fuel, a after air port 3 for supplying combustion air, and a spray nozzle 6 for spraying water of cooling fluid to the after air port 3 are further provided. It is a boiler system diagram which shows the structure of the pulverized coal burning boiler 100 which is another Example.
[0105] 本実施例の微粉炭焚きボイラ構成は図 1に示した実施例の微粉炭焚きボイラ 100と 基本構成は共通であるので説明は省略し、相違する部分についてのみ説明する。 [0105] The basic configuration of the pulverized coal fired boiler 100 of the present embodiment is the same as that of the pulverized coal fired boiler 100 of the embodiment shown in Fig. 1, so that the description thereof will be omitted and only the differences will be described.
[0106] 図 13及び図 14は図 12に示した本発明の実施例の微粉炭焚きボイラ 100に採用さ れるァフタエアポート 3を内部に収容したウィンドボックス 5の構造を夫々示しており、 図 13はァフタエアポート 3を内部に収容した本実施例のウィンドボックス 5の構造を、 図 14は図 13の D— D矢視図を示す。 [0107] 図 13及び図 14において、本実施例ではウィンドボックス 5の壁面に噴霧ノズル 6を 配置して、この噴霧ノズル 6からウィンドボックス 5内の噴霧範囲 18aに冷却流体であ る水 18を噴霧する。 FIG. 13 and FIG. 14 show the structure of the wind box 5 in which the after-air port 3 employed in the pulverized coal burning boiler 100 of the embodiment of the present invention shown in FIG. 13 shows the structure of the window box 5 of this embodiment in which the after-air port 3 is housed, and FIG. 14 shows a DD arrow view of FIG. In FIG. 13 and FIG. 14, in this embodiment, the spray nozzle 6 is arranged on the wall surface of the wind box 5, and water 18 as a cooling fluid is supplied from the spray nozzle 6 to the spray range 18 a in the wind box 5. Spray.
[0108] ウィンドボックス 5に収容されたァフタエアポート 3の開口部 3aから火炉 1の内部に 噴流 40となって投入される燃焼用空気のウィンドボックス 5内での温度は約 300°Cで あり、噴霧ノズル 6からウィンドボックス 5内の噴霧範囲 18aに噴霧した水 18が燃焼用 空気によって気化するには十分な高温である。  [0108] The temperature in the wind box 5 of the combustion air injected as a jet 40 into the furnace 1 from the opening 3a of the after-air port 3 accommodated in the wind box 5 is about 300 ° C. The water 18 sprayed from the spray nozzle 6 to the spray range 18a in the wind box 5 has a sufficiently high temperature to be vaporized by the combustion air.
[0109] ウィンドボックス 5内で気化した水 18はウィンドボックス 5内で十分に燃焼用空気の 空気流に均一混合し、ァフタエアポート 3の開口部 3aから火炉 1の内部に燃焼用空 気の噴流 40の一部として投入され、燃焼用空気の噴流 40と未燃ガス 10aとが混合 する混合領域 41に供給されて未燃ガス 10aが燃焼する火炎の温度を低下させる。  [0109] The water 18 vaporized in the wind box 5 is sufficiently mixed in the air flow of the combustion air in the wind box 5, and the combustion air is introduced into the furnace 1 from the opening 3a of the after air port 3. It is supplied as a part of the jet 40 and is supplied to the mixing region 41 where the jet 40 of combustion air and the unburned gas 10a are mixed to lower the temperature of the flame where the unburned gas 10a burns.
[0110] そして本実施例の場合においても、ァフタエアポート 3の開口部 3aに面した火炉 1 の内部に噴出する燃焼用空気の噴流 40と未燃ガス 10aとが混合する混合領域 41に 対して、噴霧ノズル 6からウィンドボックス 5内に噴霧され気化した冷却流体の水 18を 混合した燃焼用空気の噴流 40を、的確且つ均等に供給することが出来る。  [0110] Also in the case of the present embodiment, the combustion air jet 40 jetted into the furnace 1 facing the opening 3a of the after-airport 3 is mixed with the mixing region 41 where the unburned gas 10a is mixed. Thus, it is possible to accurately and evenly supply the combustion air jet 40 in which the cooling fluid water 18 sprayed and vaporized from the spray nozzle 6 into the wind box 5 is mixed.
[0111] よって本実施例では、噴霧ノズル 6から噴霧された水 18の持つ水の潜熱、顕熱によ つて混合領域 41で未燃ガス 10aが燃焼する火炎の温度の熱を奪って火炎温度の上 昇を約 1600K以下に、好ましくは約 1600K〜約 1400Kに、より確実に才卬制すること が可能となり、よってボイラで生成されるサーマル NOxの濃度を約 10〜30%低減す ること力 S出来る。  [0111] Therefore, in this embodiment, the temperature of the flame of the unburned gas 10a burning in the mixing region 41 is deprived by the latent heat of the water 18 of the water 18 sprayed from the spray nozzle 6 and the sensible heat. It is possible to more reliably control the rise in the temperature to about 1600K or less, preferably about 1600K to about 1400K, thus reducing the concentration of thermal NOx generated in the boiler by about 10-30%. Force S is possible.
[0112] 本実施例ではウィンドボックス 5内で噴霧ノズル 6から噴霧する冷却流体の水 18を 気化できればよぐ噴霧パターンにはこだわらない。また噴霧した水 18が全て気化す る必要はなぐ気化せずにウィンドボックス 5内に残った水 18はドレンとして回収して 再使用すればよい。  In this embodiment, the spray pattern is not particularly limited as long as the cooling fluid water 18 sprayed from the spray nozzle 6 in the wind box 5 can be vaporized. Moreover, it is not necessary for all the sprayed water 18 to be vaporized, and the water 18 remaining in the wind box 5 can be recovered as drainage and reused.
[0113] 本実施例によればウィンドボックス 5内で噴霧ノズル 6から噴霧する水 18を気化して ァフタエアポート 3から火炉 1の内部に投入する噴流 40自体に均一に水分を混合す ることで、確実に混合領域 41に水分を供給でき、混合領域 41で燃焼する火炎温度 の上昇を抑制することができる。 [0114] さらに噴霧した水分の蒸発によりウィンドボックス 5内の燃焼用空気の温度が低下し 、ァフタエアポート 3から火炉 1の内部に投入する噴流 40自体が低温となるので、混 合領域 41で燃焼する火炎温度の上昇がより確実に抑制できるというメリットがある。 [0113] According to this embodiment, water 18 sprayed from the spray nozzle 6 in the wind box 5 is vaporized, and water is uniformly mixed into the jet 40 itself injected into the furnace 1 from the after-air port 3. Thus, moisture can be reliably supplied to the mixing region 41 and an increase in the flame temperature combusting in the mixing region 41 can be suppressed. [0114] Further, the temperature of the combustion air in the wind box 5 decreases due to evaporation of the sprayed water, and the jet 40 itself injected into the furnace 1 from the after-air port 3 becomes low temperature. There is an advantage that the rise in the temperature of the burning flame can be more reliably suppressed.
[0115] 尚、本実施例では噴霧ノズル 6から噴霧する冷却流体は水 18の場合を説明したが 、水に替えて蒸気 20、または水と蒸気の二流体を噴霧するようにしても良い。  [0115] In the present embodiment, the cooling fluid sprayed from the spray nozzle 6 is water 18. However, instead of water, steam 20 or two fluids of water and steam may be sprayed.
[0116] また、説明は省略したが、本実施例のウィンドボックス 5に設置された噴霧ノズル 6 による冷却流体の制御は、前述した各実施例と同様に制御装置 50によって冷却流 体の流量を調節することにより行われる。  [0116] Although explanation is omitted, control of the cooling fluid by the spray nozzle 6 installed in the wind box 5 of the present embodiment is performed by controlling the flow rate of the cooling fluid by the control device 50 in the same manner as each of the embodiments described above. This is done by adjusting.
[0117] 上記した本発明の実施例によっても、ァフタエアポートからの燃焼用空気の供給で 火炉内部で未燃ガスが燃焼する際に生じる火炎温度の上昇を確実に抑制し、燃焼 時に発生するサーマル NOxの濃度を低減する信頼性の高い微粉炭焚きボイラを実 現することが出来る。  [0117] Also according to the above-described embodiment of the present invention, the supply of combustion air from the after-airport reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and occurs during combustion. A reliable pulverized coal fired boiler that reduces the concentration of thermal NOx can be realized.
実施例 7  Example 7
[0118] 次に本発明の別の実施例である微粉炭焚きボイラについて図面を用いて説明する  Next, a pulverized coal fired boiler as another embodiment of the present invention will be described with reference to the drawings.
[0119] 図 17は燃料の微粉炭を燃焼させるパーナ 2と、燃焼用空気を供給するァフタエア ポート 3と、ァフタエアポート 3に燃焼用空気を供給するダクト配管 14に冷却流体の水 を噴霧する噴霧ノズル 6を配設した本発明の別の実施例である微粉炭焚きボイラ 10 0の構成を示すボイラ系統図である。 [0119] Fig. 17 is a diagram of spraying cooling fluid water onto a burner 2 that burns pulverized coal fuel, after-air port 3 that supplies combustion air, and duct pipe 14 that supplies combustion air to after-air port 3 FIG. 4 is a boiler system diagram showing a configuration of a pulverized coal fired boiler 100 according to another embodiment of the present invention in which a spray nozzle 6 is provided.
[0120] 本実施例の微粉炭焚きボイラ構成は図 1に示した実施例の微粉炭焚きボイラ 100と 基本構成は共通であるので説明は省略し、相違する部分についてのみ説明する。  [0120] The basic configuration of the pulverized coal burning boiler 100 of the present embodiment is the same as that of the pulverized coal burning boiler 100 of the embodiment shown in Fig. 1, so that the description thereof will be omitted and only the differences will be described.
[0121] 本実施例では、ァフタエアポート 3に燃焼用空気を供給するウィンドボックス 5よりさ らに上流に位置するダクト配管 14の内部に噴霧ノズル 6を設置して、この噴霧ノズノレ 6から冷却流体の水 18をダクト配管 14の内部を流れる燃焼用空気に噴霧するため、 噴霧された水 18が混合してァフタエアポート 3に供給される高温の燃焼用空気との 滞留時間が増大する。  [0121] In this embodiment, a spray nozzle 6 is installed in the duct pipe 14 located further upstream than the wind box 5 for supplying combustion air to the after air port 3, and the spray nozzle 6 is cooled. Since the fluid water 18 is sprayed on the combustion air flowing inside the duct pipe 14, the residence time of the sprayed water 18 mixed with the high-temperature combustion air supplied to the after-air port 3 increases.
[0122] よって、噴霧ノズル 6から噴霧された水 18の気化率が向上してドレンが少なくて済 むので、噴霧ノズル 6から噴霧した冷却流体の水 18がより効率よく気化するというメリ ットカ sある。 [0122] Therefore, the vaporization rate of the water 18 sprayed from the spray nozzle 6 is improved and less draining is required, so that the cooling fluid water 18 sprayed from the spray nozzle 6 is more efficiently vaporized. There are tsuka s .
[0123] 本実施例によれば、ウィンドボックス 5の上流のダクト配管 14内で噴霧ノズル 6から 水 18を噴霧して気化し、ァフタエアポート 3から火炉 1の内部に投入する噴流 40自体 に均一に水分を混合することで、確実に混合領域 41に水分を供給でき、混合領域 4 1で燃焼する火炎温度の上昇を抑制することができる。  [0123] According to this embodiment, water 18 is sprayed from the spray nozzle 6 in the duct pipe 14 upstream of the wind box 5 to vaporize it, and the jet 40 itself injected into the furnace 1 from the after air port 3 By uniformly mixing moisture, it is possible to reliably supply moisture to the mixing region 41, and to suppress an increase in the flame temperature that burns in the mixing region 41.
[0124] さらに噴霧した水分の蒸発によりウィンドボックス 5内に供給する燃焼用空気の温度 が低下してァフタエアポート 3から火炉 1の内部に投入する噴流 40自体が低温となる ので、混合領域 41で燃焼する火炎温度の上昇がより確実に抑制できるというメリット 力 sある。 [0124] Further, the temperature of the combustion air supplied into the wind box 5 is lowered by evaporation of the sprayed water, and the jet 40 itself injected into the furnace 1 from the after-air port 3 becomes a low temperature. in some merit force s that increase of flame temperature for combustion can be more reliably suppressed.
[0125] 尚、本実施例では噴霧ノズル 6から噴霧する冷却流体は水 18の場合を説明したが 、水に替えて蒸気 20、または水と蒸気の二流体を噴霧するようにしても良い。  In the present embodiment, the case where the cooling fluid sprayed from the spray nozzle 6 is water 18 has been described. However, instead of water, steam 20 or two fluids of water and steam may be sprayed.
[0126] また、説明は省略したが、本実施例のウィンドボックス 5に設置された噴霧ノズル 6 による冷却流体の制御は、前述した各実施例と同様に制御装置 50によって冷却流 体の流量を調節することにより行われる。  [0126] Although explanation is omitted, control of the cooling fluid by the spray nozzle 6 installed in the window box 5 of the present embodiment is performed by controlling the flow rate of the cooling fluid by the control device 50 in the same manner as each of the embodiments described above. This is done by adjusting.
[0127] よって本実施例では、噴霧ノズル 6から噴霧された水 18の持つ水の潜熱、顕熱によ つて混合領域 41で未燃ガス 10aが燃焼する火炎の温度の熱を奪って火炎温度の上 昇を約 1600K以下に、好ましくは約 1600K〜約 1400Kに、より確実に才卬制すること が可能となり、よってボイラで生成されるサーマル NOxの濃度を約 10〜30%低減す ること力 S出来る。  [0127] Therefore, in this embodiment, the temperature of the flame at which the unburned gas 10a burns in the mixing region 41 is deprived by the latent heat of water 18 of the water 18 sprayed from the spray nozzle 6 and the sensible heat. It is possible to more reliably control the rise in the temperature to about 1600K or less, preferably about 1600K to about 1400K, thus reducing the concentration of thermal NOx generated in the boiler by about 10-30%. Force S is possible.
[0128] 上記した本発明の実施例によっても、ァフタエアポートからの燃焼用空気の供給に よって火炉内部で未燃ガスが燃焼する際に生じる火炎温度の上昇を確実に抑制し、 燃焼時に発生するサーマル NOxの濃度を低減する信頼性の高い微粉炭焚きボイラ を実現することが出来る。  [0128] Also according to the above-described embodiment of the present invention, the supply of combustion air from the after-air port reliably suppresses the rise in flame temperature that occurs when unburned gas burns inside the furnace, and occurs during combustion. It is possible to realize a highly reliable pulverized coal fired boiler that reduces the concentration of thermal NOx.
実施例 8  Example 8
[0129] 次に本発明の更に別の実施例である微粉炭焚きボイラについて図面を用いて説明 する。  [0129] Next, a pulverized coal fired boiler as still another embodiment of the present invention will be described with reference to the drawings.
[0130] 図 18は燃料の微粉炭を噴射して燃焼させるパーナ 2と、燃焼用空気を供給する主 ァフタエアポート 61と、水と蒸気との双方を噴霧する噴霧ノズル 6を有して燃焼用空 気を供給する副ァフタエアポート 60とを火炉 1の壁面に備えた本発明の更に別の実 施例である微粉炭焚きボイラ 100の構成を示すボイラ系統図である。 [0130] Fig. 18 shows combustion with a burner 2 for injecting and burning fuel pulverized coal, a main after-air port 61 for supplying combustion air, and a spray nozzle 6 for spraying both water and steam. Sky FIG. 3 is a boiler system diagram showing a configuration of a pulverized coal fired boiler 100 which is still another embodiment of the present invention in which an auxiliary after-air port 60 for supplying air is provided on the wall surface of the furnace 1.
[0131] 本実施例の微粉炭焚きボイラの構成は図 17に示した実施例の微粉炭焚きボイラ 1[0131] The configuration of the pulverized coal fired boiler of this example is the pulverized coal fired boiler of the example shown in FIG.
00と基本構成は共通であるので、共通の構成についての説明は省略し、相違する 部分にっレ、てのみ説明する。 Since the basic configuration is common to 00, the description of the common configuration will be omitted, and only the differences will be described.
[0132] 図 18に示した本実施例の微粉炭焚きボイラ 100において、火炉 1の壁面には、火 炉 1の内部を流れる燃焼ガス 10の流れ方向に沿って上流側に副ァフタエアポート 60 が設置され、下流側に主ァフタエアポート 61が設置されている。 [0132] In the pulverized coal fired boiler 100 of the present embodiment shown in Fig. 18, the sub-after-airport 60 is provided upstream of the wall surface of the furnace 1 along the flow direction of the combustion gas 10 flowing inside the furnace 1. The main after-air port 61 is installed downstream.
[0133] さらに、副ァフタエアポート 60には噴霧ノズル 6が備えられており、この噴霧ノズル 6 力 水又は水と蒸気との双方を噴霧する構成となっている。 Further, the sub-after air port 60 is provided with a spray nozzle 6, and the spray nozzle 6 is configured to spray water or both water and steam.
[0134] 本実施例の微粉炭焚きボイラ 100では、副ァフタエアポート 60から供給する空気量 は主ァフタエアポート 61から供給する空気量よりも少なくなるように設定している。 In the pulverized coal burning boiler 100 of the present embodiment, the amount of air supplied from the sub-after air port 60 is set to be smaller than the amount of air supplied from the main after-air port 61.
[0135] 上記構成の微粉炭焚きボイラ 100において、副ァフタエアポート 60から火炉 1内に 噴出された空気の流れ 62、及び主ァフタエアポート 61から火炉 1内に噴出された空 気の流れ 63を図 18に模式的に示す。 [0135] In the pulverized coal-fired boiler 100 configured as described above, the air flow 62 injected into the furnace 1 from the sub-after air port 60 and the air flow injected into the furnace 1 from the main after-air port 61 63 Is schematically shown in FIG.
[0136] 副ァフタエアポート 60から火炉 1内に噴出して供給された空気の流れ 62は、噴出 する流量が少ないことから火炉 1の内壁面に沿って下流側に流れる。 [0136] The air flow 62 blown into the furnace 1 from the auxiliary after-airport 60 and supplied to the furnace 1 flows downstream along the inner wall surface of the furnace 1 because the flow rate of the blown air is small.
[0137] 一方、主ァフタエアポート 61から噴出して供給された空気の流れ 63は、噴出する 流量が多いことから火炉 1の内部の中央部まで到達する。 [0137] On the other hand, the air flow 63 ejected from the main after-air port 61 reaches the central part inside the furnace 1 due to the large flow rate of ejection.
[0138] 火炉 1の内部では、上流から下流に向かって流れる燃焼ガス 10aに対して火炉 1の 壁面近くでは前記空気の流れ 62、 63のうち、燃焼ガス 10aとの混合時の燃焼ガスの 温度は、上流側となる空気の流れ 62の方が高くなる。 [0138] In the furnace 1, the temperature of the combustion gas at the time of mixing with the combustion gas 10a out of the air flows 62 and 63 near the wall of the furnace 1 with respect to the combustion gas 10a flowing from upstream to downstream Is higher in the upstream air flow 62.
[0139] また、火炉 1の中央部は火炉 1の壁面から遠いため燃焼ガス 10aの温度が最も高く なる。 [0139] Further, since the center portion of the furnace 1 is far from the wall surface of the furnace 1, the temperature of the combustion gas 10a is the highest.
[0140] ところで、未燃焼分を含む高温の燃焼ガス 10aと供給された空気とが混合すると燃 焼反応が進み温度が上昇するが、この時、空気中や燃焼ガス 10a中の窒素ガスが高 温の酸化雰囲気で酸化されて窒素酸化物（NOx)が生成する、 V、わゆるサーマル N Oxが生成し、このサーマル NOxは温度が高くなるほどその生成量が増える。 [0141] 本実施例の微粉炭焚きボイラ 100では、上流側の副ァフタエアポート 60に備えた 噴霧ノズル 6から水を噴霧するように構成しているので、副ァフタエアポート 60から火 炉 1内に供給される空気の流れ 62の中に水分を多く含む。 [0140] By the way, when the high-temperature combustion gas 10a containing unburned components is mixed with the supplied air, the combustion reaction proceeds and the temperature rises. At this time, the nitrogen gas in the air and the combustion gas 10a is high. Nitrogen oxide (NOx) is produced by oxidation in a warm oxidizing atmosphere. V, so-called thermal NOx is produced, and the amount of thermal NOx produced increases as the temperature increases. [0141] In the pulverized coal fired boiler 100 of the present embodiment, water is sprayed from the spray nozzle 6 provided in the upstream side after-air port 60, and therefore, from the side after air port 60 to the furnace 1 The air flow 62 supplied therein contains a lot of moisture.
[0142] この噴霧ノズル 6から噴霧する水は、蒸発の際に蒸発熱を周囲の空気から奪い、空 気の温度を低下させる。  [0142] The water sprayed from the spray nozzle 6 takes the heat of evaporation from the surrounding air during evaporation, and lowers the temperature of the air.
[0143] また空気の流れ 62の中に水分を多く含んで比熱が増えることから、副ァフタエアポ ート 60から噴出する空気の流れ 62と燃焼ガス 10aとが混合する際に、この空気の流 れ 62に多く含まれた水分によって燃焼反応を抑制して燃焼温度を低く抑えることが できる。  [0143] Further, since the air flow 62 contains a lot of water and the specific heat increases, the air flow 62 ejected from the sub-after air port 60 and the combustion gas 10a are mixed with each other. Combustion reaction can be suppressed by the moisture contained in 62 so that the combustion temperature can be kept low.
[0144] このため、燃焼反応とともに生成するサーマル NOxの生成量を低く抑えることがで きる。  [0144] Therefore, the amount of thermal NOx generated along with the combustion reaction can be kept low.
[0145] さらに、本実施例の微粉炭焚きボイラ 100では、燃焼ガス 10aと混合後の水分を含 む空気の流れ 62の一部は、その下流側に位置する主ァフタエアポート 61から噴出 する空気の流れ 63と混合する。  [0145] Furthermore, in the pulverized coal fired boiler 100 of the present embodiment, a part of the air flow 62 containing moisture after mixing with the combustion gas 10a is ejected from the main after-air port 61 located downstream thereof. Mix with air stream 63.
[0146] この空気の流れ 63と水分を含む空気の流れ 62の一部が混合する際に、火炉 1の 内壁近傍部 64で燃焼した既燃焼ガスの一部が主ァフタエアポート 61から噴出する 空気の流れ 63に巻き込まれるために、空気の流れ 63の最外周部分に水分を含む既 燃焼ガスが流れる。  [0146] When the air flow 63 and a part of the moisture-containing air flow 62 are mixed, a part of the burned gas combusted in the vicinity of the inner wall 64 of the furnace 1 is ejected from the main after-air port 61. In order to get caught in the air flow 63, the burned gas containing moisture flows in the outermost peripheral portion of the air flow 63.
[0147] このため、水分を含む未燃焼ガス及び空気の流れ 63と燃焼ガス 10aとが混合する 時に、既燃焼ガスゃ既燃焼ガスに含まれる水分の比熱によって燃焼温度が低く抑え られることになり、この結果、火炉 1の中央部で生成するサーマル NOxの生成量を低 く才卬えること力 Sできる。  [0147] For this reason, when the unburned gas containing moisture and the air flow 63 and the combustion gas 10a are mixed, the combustion temperature is kept low by the specific heat of the moisture contained in the already burned gas. As a result, the ability to reduce the amount of thermal NOx produced in the center of the furnace 1 is low.
[0148] 上述したように、ァフタエアポートから噴出する空気の流れと燃焼ガス 10aとの混合 時に、比較的上流側の火炉 1の内壁近傍部 64や火炉 1の中央部 65のように高温に なりやすい部分に水分を多く含む空気の流れや水分を含む既燃焼ガスを供給させる ことで、サーマル NOxの生成量を低く抑えることができる。  [0148] As described above, when the flow of air ejected from the after-air port and the combustion gas 10a are mixed, the temperature rises to a relatively high temperature, such as the vicinity 64 of the inner wall of the furnace 1 on the relatively upstream side or the central part 65 of the furnace 1. By supplying a flow of air containing a lot of moisture and a burned gas containing moisture to the likely part, the amount of thermal NOx produced can be kept low.
[0149] さらに水分を多く含む既燃焼ガスを空気の流れ 63の最外周部に巻き込むことで、 水の供給量の低減とサーマル NOxの抑制とを両立できる。 [0150] また、水を供給すると熱効率は低下するが、サーマル NOxの抑制によって火炉 1の 下流での NOxの低減に必要な機器の動力や注入する薬品使用量を抑制できる。 [0149] By entraining the already burned gas containing more water around the outermost peripheral portion of the air flow 63, it is possible to reduce both the amount of water supply and the suppression of thermal NOx. [0150] Although the thermal efficiency decreases when water is supplied, the power of equipment necessary for reducing NOx downstream of the furnace 1 and the amount of chemicals used for injection can be suppressed by suppressing thermal NOx.
[0151] 本実施例では火炉 1の上流側に設置した副ァフタエアポート 60から供給する空気 の流れ 62の空気量が下流側に設置した主ァフタエアポート 61から供給する空気の 流れ 63の空気量よりも少量に設定した場合の状況を示したが、逆に上流側の副ァフ タエアポート 60から供給する空気の流れ 62の空気量が主ァフタエアポート 61から供 給する空気の流れ 63の空気量よりも多量となるように設定した場合でもほぼ同様の ¾]果を得ること力できる。  [0151] In this embodiment, the air flow 62 supplied from the sub-after air port 60 installed on the upstream side of the furnace 1 is the air flow supplied from the main after-air port 61 installed on the downstream side 63 air However, the flow of air supplied from the upstream secondary air port 60 is the same as the flow of air supplied from the main after air port 61. Even when it is set to be larger than the amount of air, it is possible to obtain substantially the same results.
[0152] 尚、この場合に発生するサーマル NOxを低く抑えるためには、前述の場合よりも副 ァフタエアポート 60に備えた噴霧ノズル 6から噴霧する水の供給量が多くなることは 前述の通り自明である。  [0152] It should be noted that in order to keep the thermal NOx generated in this case low, the amount of water sprayed from the spray nozzle 6 provided in the sub-lifter air port 60 is larger than that described above as described above. It is self-explanatory.
[0153] 但し、火炉 1の上流側で副ァフタエアポート 60から供給する空気の流れ 62の多量 の空気量が燃焼ガス 10aと混合するため、火炉出口での未燃焼分を低減することが できる。  [0153] However, since a large amount of air in the air flow 62 supplied from the sub-after air port 60 on the upstream side of the furnace 1 is mixed with the combustion gas 10a, the amount of unburned gas at the furnace outlet can be reduced. .
[0154] 尚、本実施例では噴霧ノズル 6から噴霧する冷却流体は水 18の場合を説明したが 、水 18に替えて蒸気 20、または水 18と蒸気 20との二流体を噴霧するようにしても良 い。  [0154] In this embodiment, the cooling fluid sprayed from the spray nozzle 6 is water 18. However, instead of the water 18, steam 20 or two fluids of water 18 and steam 20 are sprayed. It's okay.
[0155] また、本実施例では噴霧ノズル 6の先端の位置を副ァフタエアポート 60の開口部に 設けた場合を示した力 S、図 12に示した本発明の実施例 6や図 17に示した本発明の 実施例 7と同様に副ァフタエアポート 60を収容するウィンドボックス 5aや、このウィン ドボックス 5aに空気を供給するダクト配管 14に前記噴霧ノズル 6を設置した場合も上 述の効果が得られる。  [0155] Further, in this embodiment, the force S is shown when the position of the tip of the spray nozzle 6 is provided in the opening of the sub-after air port 60, and in Embodiment 6 and Figure 17 of the present invention shown in FIG. Similarly to the embodiment 7 of the present invention shown above, the above-mentioned spray nozzle 6 is also installed in the wind box 5a for accommodating the auxiliary after-air port 60 and the duct pipe 14 for supplying air to the window box 5a. An effect is obtained.
[0156] また、この噴霧ノズル 6を上記した各位置に設置した場合に得られる効果は、図 7に 示した実施例 6や図 17に示した実施例 7の場合と同じである。  [0156] Further, the effects obtained when the spray nozzle 6 is installed at each position described above are the same as those in the sixth embodiment shown in FIG. 7 and the seventh embodiment shown in FIG.
[0157] さらに、図 5及び図 6に示した本発明の第 2の実施例のように、噴霧ノズル 6を直進 流路 30の外周側となる旋回流路 31の開口部に設けることも可能である。 Furthermore, as in the second embodiment of the present invention shown in FIGS. 5 and 6, the spray nozzle 6 can be provided at the opening of the swirl flow path 31 on the outer peripheral side of the straight flow path 30. It is.
[0158] この場合、旋回流により噴霧ノズル 6から噴出する水 18は空気の流れ 62の外周部 を多く流れるため、燃焼ガス 10aと空気の流れ 62との混合部分の水分が多くなるの で、サーマル NOxの濃度を少ない水使用量にて低減することが可能となる。 [0158] In this case, the water 18 ejected from the spray nozzle 6 by the swirling flow flows in a large amount in the outer peripheral portion of the air flow 62, so that the water content in the mixed portion of the combustion gas 10a and the air flow 62 increases. Therefore, it is possible to reduce the concentration of thermal NOx with a small amount of water used.
[0159] また、本実施例の微粉炭焚きボイラ 100では、副ァフタエアポート 60に備えた噴霧 ノズル 6から噴霧する冷却流体の制御は前述した各実施例と同様に制御装置 50によ つて冷却流体の流量を適量に調節することにより行われる。 [0159] In the pulverized coal burning boiler 100 of the present embodiment, the control of the cooling fluid sprayed from the spray nozzle 6 provided in the auxiliary after-air port 60 is controlled by the control device 50 in the same manner as in each of the embodiments described above. This is done by adjusting the flow rate of the fluid to an appropriate amount.
[0160] 即ち、 NOx検出器 55で検出された排ガス 11の NOx濃度信号を制御装置 50に入 力し、この制御装置 50によって設定された所望の NOX設定値と NOx濃度信号とを 比較して排ガス 11の NOx濃度が所望の設定値を維持するように火炉 1の内部に噴 霧ノズル 6から噴霧すべき冷却流体の流量指令信号を演算し、この指令信号を冷却 流体の水 18を噴霧ノズル 6に供給する配管 42に設けた流量調整用のバルブ 17に 出力するように構成して冷却流体の流量を適量に調節し、サーマル NOxの濃度を低 減している。 That is, the NOx concentration signal of the exhaust gas 11 detected by the NOx detector 55 is input to the control device 50, and the desired NOX set value set by the control device 50 is compared with the NOx concentration signal. The flow rate command signal of the cooling fluid to be sprayed from the spray nozzle 6 is calculated in the furnace 1 so that the NOx concentration of the exhaust gas 11 maintains the desired set value, and this command signal is used as the spray fluid water 18 spray nozzle. It is configured to output to the flow rate adjustment valve 17 provided in the pipe 42 to be supplied to 6, and the flow rate of the cooling fluid is adjusted to an appropriate amount to reduce the concentration of thermal NOx.
[0161] 上記した本実施例の微粉炭焚きボイラ 100では、ァフタエアポートからの燃焼用空 気の供給によって火炉内部で未燃ガスが燃焼する際に生じる火炎温度の上昇を確 実に抑制し、燃焼時に発生するサーマル NOxの濃度を低減する信頼性の高!/、微粉 炭焚きボイラを実現することが出来る。  [0161] In the pulverized coal-fired boiler 100 of the present embodiment described above, an increase in the flame temperature that occurs when unburned gas burns inside the furnace due to the supply of combustion air from the after-air port is reliably suppressed, A highly reliable! / Pulverized coal fired boiler that reduces the concentration of thermal NOx generated during combustion can be realized.
産業上の利用可能性  Industrial applicability
[0162] 本発明は、燃料として微粉炭を使用する微粉炭焚きボイラに係り、特にサーマル窒 素酸化物の生成を抑制する微粉炭焚きボイラに適用可能であり、既存の微粉炭焚き ボイラにも適用が容易である。 [0162] The present invention relates to a pulverized coal fired boiler that uses pulverized coal as a fuel, and is particularly applicable to a pulverized coal fired boiler that suppresses the formation of thermal nitrogen oxides, and also to an existing pulverized coal fired boiler. Easy to apply.
図面の簡単な説明  Brief Description of Drawings
[0163] [図 1]本発明の一実施例である微粉炭焚きボイラの構成を示すボイラ系統図。本発明 の実施例によるァフタエアポートの構造図。  FIG. 1 is a boiler system diagram showing the configuration of a pulverized coal fired boiler according to an embodiment of the present invention. 1 is a structural diagram of a after airport according to an embodiment of the present invention.
[図 2]図 1に示した本発明の一実施例の微粉炭焚きボイラに適用される噴霧ノズルを 備えたァフタエアポートの構造を示す断面図。  2 is a cross-sectional view showing the structure of a after-airport provided with a spray nozzle applied to the pulverized coal fired boiler of one embodiment of the present invention shown in FIG.
[図 3]図 2に示した噴霧ノズルを備えたァフタエアポートの A— A矢視図。  [FIG. 3] AA arrow view of the after-airport equipped with the spray nozzle shown in FIG.
[図 4]図 2に示したァフタエアポートに備えられた噴霧ノズルの噴霧パターンの一例を 示す図。  4 is a diagram showing an example of a spray pattern of a spray nozzle provided in the after air port shown in FIG. 2.
[図 5]図 1に示した本発明の一実施例の微粉炭焚きボイラに適用される噴霧ノズルを 備えたァフタエアポートの他の構造を示す断面図。 FIG. 5 shows a spray nozzle applied to the pulverized coal fired boiler according to the embodiment of the present invention shown in FIG. Sectional drawing which shows the other structure of the after airport provided.
[図 6]図 5に示した噴霧ノズルを備えたァフタエアポートの B— B矢視図。  FIG. 6 is a BB arrow view of the after air port equipped with the spray nozzle shown in FIG.
[図 7]図 1に示した本発明の一実施例の微粉炭焚きボイラに適用される噴霧ノズルを 備えたァフタエアポートの更に他の構造を示す断面図。  FIG. 7 is a cross-sectional view showing still another structure of the after-airport provided with the spray nozzle applied to the pulverized coal burning boiler of one embodiment of the present invention shown in FIG.
[図 8]図 7に示した噴霧ノズルを備えたァフタエアポートの C— C矢視図。  FIG. 8 is a CC arrow view of the after air port equipped with the spray nozzle shown in FIG.
[図 9]図 1に示した本発明の一実施例の微粉炭焚きボイラに適用される噴霧ノズルを 備えたァフタエアポートの別の構造を示す断面図。  FIG. 9 is a cross-sectional view showing another structure of a after-airport provided with a spray nozzle applied to the pulverized coal fired boiler of one embodiment of the present invention shown in FIG.
[図 10]図 1に示した本発明の一実施例の微粉炭焚きボイラに適用される噴霧ノズノレ を備えたァフタエアポートの更に別の構造を示す断面図。  FIG. 10 is a cross-sectional view showing still another structure of the after-airport provided with the spray nozzle that is applied to the pulverized coal burning boiler of the embodiment of the present invention shown in FIG.
[図 11]本発明の他の実施例である微粉炭焚きボイラの構成を示すボイラ系統図。  FIG. 11 is a boiler system diagram showing the configuration of a pulverized coal fired boiler according to another embodiment of the present invention.
[図 12]本発明の更に他の実施例である微粉炭焚きボイラの構成を示すボイラ系統図 FIG. 12 is a boiler system diagram showing the configuration of a pulverized coal fired boiler according to still another embodiment of the present invention.
[図 13]図 12に示した本発明の更に他の実施例である微粉炭焚きボイラに適用される 噴霧ノズルを備えたウィンドボックスの構造を示す断面図。 FIG. 13 is a cross-sectional view showing the structure of a wind box provided with a spray nozzle applied to a pulverized coal fired boiler as still another embodiment of the present invention shown in FIG.
[図 14]図 13に示した噴霧ノズルを備えたウイイドボックスの D— D矢視図。  FIG. 14 is a DD arrow view of a wind box provided with the spray nozzle shown in FIG.
[図 15]図 1に示した本発明の一実施例の微粉炭焚きボイラに備えられた冷却流体の 噴霧量を制御する制御装置を示すブロック図。  FIG. 15 is a block diagram showing a control device that controls the spray amount of the cooling fluid provided in the pulverized coal fired boiler of one embodiment of the present invention shown in FIG. 1.
[図 16]図 15に示した制御装置における冷却流体を調整するバルブを制御する特性 図を示すものであり、図 16の (A)は排ガスの NOx濃度に対するバルブの開度との関 係を示した特性図、図 16の（B)はボイラ負荷に対するバルブの開度との関係を示し た特性図。  [FIG. 16] A characteristic diagram for controlling the valve for adjusting the cooling fluid in the control device shown in FIG. 15 is shown. (A) in FIG. 16 shows the relationship between the NOx concentration of the exhaust gas and the opening degree of the valve. Fig. 16B is a characteristic diagram showing the relationship between the valve opening and the boiler load.
[図 17]本発明の別の実施例である微粉炭焚きボイラの構成を示すボイラ系統図。  FIG. 17 is a boiler system diagram showing a configuration of a pulverized coal burning boiler that is another embodiment of the present invention.
[図 18]本発明の更に別の実施例である微粉炭焚きボイラの構成を示すボイラ系統図 符号の説明 FIG. 18 is a boiler system diagram showing the configuration of a pulverized coal fired boiler which is still another embodiment of the present invention.
1 :火炉、 2 :パーナ、 3 :ァフタエアポート、 3a :ァフタエアポートの開口部、 4 :バー ナのウィンドボックス、 5 5a :ァフタエアポートのウィンドボックス、 6 :噴霧ノズル、 7 :ミ ノレ、 8 9 :ダンバ、 10 :燃焼ガス、 10a :未燃ガス、 11 :排ガス、 12 :ブロア、 13 :熱交 換器、 14:ダクト配管、 15:煙突、 16:ポンプ、 17、 22:バルブ、 18:水、 18a:噴霧範 囲、 20:蒸気、 21:蒸気タンク、 30:直進流路、 31:旋回流路、 33、 34:ダンバ、 40: 噴流、 41:混合領域、 42、 43:配管、 50:制御装置、 51:ボイラ負荷設定器、 52:N Ox濃度設定器、 53:噴霧流量演算器、 55:NOx検出器、 60:副ァフタエアポート、 61:主ァフタエアポート、 100:微粉炭焚きボイラ。 1: furnace, 2: panner, 3: after-air port, 3a: after-air port opening, 4: burner window box, 5 5a: after-air port window box, 6: spray nozzle, 7: minor 8 9: Dunbar, 10: Combustion gas, 10a: Unburned gas, 11: Exhaust gas, 12: Blower, 13: Heat exchange Exchanger, 14: Duct piping, 15: Chimney, 16: Pump, 17, 22: Valve, 18: Water, 18a: Spray range, 20: Steam, 21: Steam tank, 30: Straight passage, 31: Swivel Flow path, 33, 34: Damper, 40: Jet, 41: Mixing area, 42, 43: Piping, 50: Control device, 51: Boiler load setting device, 52: N Ox concentration setting device, 53: Spray flow rate calculator 55: NOx detector, 60: Sub-after air port, 61: Main after-air port, 100: Pulverized coal fired boiler.

Claims

請求の範囲 The scope of the claims
[1] 火炉と、この火炉の壁面に設けられて燃料の微粉炭を火炉内に供給して燃焼させ るパーナと、パーナの設置位置より下流側の火炉の壁面に設けられて燃焼用空気を 火炉の内部に供給するァフタエアポートを備えた微粉炭焚きボイラにおいて、水又は 蒸気、又は水と蒸気の二流体を火炉の内部に供給する噴霧ノズルをァフタエアポー トの燃焼用空気の噴出口の近傍に設けて、ァフタエアポートから供給される燃焼用 空気と共に噴霧ノズルから水又は蒸気、又は水と蒸気の二流体を火炉の内部に供給 するように構成したことを特徴とする微粉炭焚きボイラ。  [1] A furnace, a burner installed on the wall of the furnace to supply and burn pulverized coal of fuel into the furnace, and a burner installed on the furnace wall downstream of the installation position of the burner. In a pulverized coal-fired boiler equipped with a after-air port that supplies the interior of the furnace, a spray nozzle that supplies water or steam or two fluids of water and steam to the interior of the furnace is located near the combustion air outlet of the after-air port The pulverized coal fired boiler is configured to supply water or steam or two fluids of water and steam from the spray nozzle together with combustion air supplied from the after-air port to the inside of the furnace.
[2] 請求項 1に記載の微粉炭焚きボイラにお!/、て、前記ァフタエアポートを前記火炉内 の燃焼ガスの流れ方向に複数設置し、前記複数設置したァフタエアポートのうち、前 記火炉内の燃焼ガスの流れ方向の上流側に設置したァフタエアポートから水又は蒸 気、水と蒸気の二流体を火炉の内部に供給するように構成したことを特徴とする微粉 炭焚きボイラ。  [2] In the pulverized coal-fired boiler according to claim 1, a plurality of after-air ports are installed in the flow direction of the combustion gas in the furnace, and the front air ports among the plurality of after-air ports installed A pulverized coal-fired boiler characterized in that water or steam, or two fluids of water and steam are supplied into the furnace from a after-air port installed upstream in the flow direction of combustion gas in the furnace. .
[3] 請求項 2に記載の微粉炭焚きボイラにおいて、前記複数設置したァフタエアポート のうち、前記火炉内の燃焼ガスの流れ方向の上流側に設置したァフタエアポートから 供給する燃焼用空気は、燃焼ガスの流れ方向の下流側に設置したァフタエアポート 力 供給する燃焼用空気に比べて空気量を少なくして供給するように構成したことを 特徴とする微粉炭焚きボイラ。  [3] In the pulverized coal fired boiler according to claim 2, the combustion air supplied from the after air port installed upstream of the plurality of after air ports installed in the flow direction of the combustion gas in the furnace is After-airport installed downstream in the flow direction of the combustion gas A pulverized coal fired boiler configured to supply with a reduced amount of air compared to the combustion air supplied.
[4] 請求項 2または請求項 3に記載の微粉炭焚きボイラにおいて、前記水又は蒸気、又 は水と蒸気の二流体を火炉の内部に供給するァフタエアポートは、その内部に燃焼 用空気を直進流として噴出する直進流の流路と、この直進流の流路の外周側に設置 されて燃焼用空気を旋回流として噴出する旋回流の流路とを備え、前記水又は蒸気 、又は水と蒸気の二流体を前記旋回流の流路から噴出させるように構成したことを特 徴とする微粉炭焚きボイラ。  [4] In the pulverized coal fired boiler according to claim 2 or claim 3, the after-air port for supplying the water or steam or two fluids of water and steam to the inside of the furnace is provided with combustion air therein. A straight flow channel that jets as a straight flow, and a swirl flow channel that is installed on the outer peripheral side of the straight flow channel and jets combustion air as a swirl flow, and the water or steam, or A pulverized coal fired boiler, characterized in that two fluids of water and steam are ejected from the flow path of the swirling flow.
[5] 請求項 1から請求項 4のレ、ずれかに記載の微粉炭焚きボイラにお!/、て、微粉炭焚き ボイラから排出される排ガスの NOx濃度を検出する NOx濃度検出器を設置し、この NOx濃度検出器の NOx濃度に基づいて噴霧ノズルから火炉の内部に供給する水 又は蒸気、水と蒸気の二流体の流量を制御する制御装置を設置したことを特徴とす る微粉炭焚きボイラ。 [5] In the pulverized coal fired boiler according to claims 1 to 4 !, a NOx concentration detector is installed to detect the NOx concentration of the exhaust gas discharged from the pulverized coal fired boiler. A control device is installed to control the flow rate of water or steam, or water and steam supplied from the spray nozzle to the inside of the furnace based on the NOx concentration of this NOx concentration detector. A pulverized coal fired boiler.
[6] 請求項 1から請求項 4のレ、ずれかに記載の微粉炭焚きボイラにお!/、て、微粉炭焚き ボイラの負荷に基づいて噴霧ノズルから火炉の内部に供給する水又は蒸気、又は水 と蒸気の二流体の流量を制御する制御装置を設置したことを特徴とする微粉炭焚き ボイラ。  [6] In the pulverized coal-fired boiler according to any one of claims 1 to 4, the water or steam supplied from the spray nozzle to the inside of the furnace based on the load of the pulverized coal-fired boiler Or a pulverized coal fired boiler, characterized in that a control device for controlling the flow rate of two fluids of water and steam is installed.
[7] 請求項 1に記載の微粉炭焚きボイラにお!/、て、水又は蒸気、又は水と蒸気の二流 体を火炉の内部に供給する噴霧ノズルの噴出口はァフタエアポートの噴出ロカ 噴 出する燃焼用空気の噴流の上流側に位置するように配設したことを特徴とする微粉 炭焚きボイラ。  [7] In the pulverized coal-fired boiler according to claim 1, the nozzle of the spray nozzle that supplies water, steam, or a two-stream of water and steam to the inside of the furnace is the outlet airport A pulverized coal-fired boiler, characterized by being disposed upstream of a jet of combustion air to be ejected.
[8] 火炉と、この火炉の壁面に設けられて燃料の微粉炭を火炉内に供給して燃焼させ るパーナと、パーナの設置位置より下流側の火炉の壁面に設けられて燃焼用空気を 火炉の内部に供給するァフタエアポートを有するウィンドボックスと、このウィンドボッ タスに外部から燃焼用空気を導くダ外配管を備えた微粉炭焚きボイラにおいて、水 又は蒸気、又は水と蒸気の二流体を供給する噴霧ノズルをウィンドボックスの内部又 はダクト配管の内部に設け、この噴霧ノズルからウィンドボックスの内部又はダクト配 管の内部に噴霧した水又は蒸気、又は水と蒸気の二流体をウィンドボックスに備えた ァフタエアポートの噴出ロカ 燃焼用空気と共に火炉の内部に供給するように構成 したことを特徴とする微粉炭焚きボイラ。  [8] A furnace, a burner provided on the wall of the furnace to supply pulverized coal of fuel into the furnace for combustion, and a burner provided on the wall of the furnace downstream from the installation position of the burner. In a pulverized coal-fired boiler equipped with a wind box having a after-air port for supplying to the inside of the furnace and an external pipe for introducing combustion air from the outside to the wind bot, water or steam, or two fluids of water and steam are supplied. The spray nozzle to be supplied is installed inside the wind box or inside the duct pipe, and water or steam sprayed from the spray nozzle into the inside of the wind box or inside the duct pipe, or two fluids of water and steam are supplied to the wind box. After-airport jet loca equipped with a pulverized coal fired boiler configured to be supplied into the furnace together with combustion air.
[9] 請求項 8に記載の微粉炭焚きボイラにおいて、微粉炭焚きボイラから排出される排 ガスの NOx濃度を検出する NOx濃度検出器を設置し、この NOx濃度検出器の NO X濃度に基づいて噴霧ノズルから火炉の内部に供給する水又は蒸気、又は水と蒸気 の二流体の流量を制御する制御装置を設置したことを特徴とする微粉炭焚きボイラ。  [9] In the pulverized coal fired boiler according to claim 8, a NOx concentration detector that detects the NOx concentration of exhaust gas discharged from the pulverized coal fired boiler is installed, and based on the NOx concentration of this NOx concentration detector A pulverized coal-fired boiler is provided with a control device for controlling the flow rate of water or steam supplied from the spray nozzle to the inside of the furnace or two fluids of water and steam.
[10] 請求項 8に記載の微粉炭焚きボイラにおいて、微粉炭焚きボイラの負荷に基づいて 噴霧ノズルから火炉の内部に供給する水又は蒸気、又は水と蒸気の二流体の流量 を制御する制御装置を設置したことを特徴とする微粉炭焚きボイラ。  [10] In the pulverized coal fired boiler according to claim 8, control for controlling the flow rate of water or steam supplied from the spray nozzle to the inside of the furnace or two fluids of water and steam based on the load of the pulverized coal fired boiler A pulverized coal-fired boiler characterized by the installation of equipment.
PCT/JP2007/071525 2006-11-08 2007-11-06 Pulverized coal boiler WO2008056650A1 (en)

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EP2083216A4 (en) 2013-03-06

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