EP2083216A1 - Kohlenstaubkessel - Google Patents

Kohlenstaubkessel Download PDF

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Publication number
EP2083216A1
EP2083216A1 EP07831257A EP07831257A EP2083216A1 EP 2083216 A1 EP2083216 A1 EP 2083216A1 EP 07831257 A EP07831257 A EP 07831257A EP 07831257 A EP07831257 A EP 07831257A EP 2083216 A1 EP2083216 A1 EP 2083216A1
Authority
EP
European Patent Office
Prior art keywords
furnace
pulverized coal
air
steam
water
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP07831257A
Other languages
English (en)
French (fr)
Other versions
EP2083216A4 (de
Inventor
Akihito Orii
Masayuki Taniguchi
Yuki Kamikawa
Hironobu Kobayashi
Miki Shimogouri
Toshihiko Mine
Shinichiro Nomura
Akira Baba
Yusuke Ochi
Koji Kuramashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Hitachi Power Systems Ltd
Original Assignee
Babcock Hitachi KK
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 KK filed Critical Babcock Hitachi KK
Publication of EP2083216A1 publication Critical patent/EP2083216A1/de
Publication of EP2083216A4 publication Critical patent/EP2083216A4/de
Withdrawn legal-status Critical Current

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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 boiler that uses pulverized coal as a fuel, more particularly to a pulverized coal boiler that suppresses the generation of thermal nitrogen oxides.
  • Pulverized coal boilers use the two-stage combustion method because the concentrations of NOx generated during the combustion of pulverized coal used as a fuel need to be reduced.
  • the two-stage combustion method is applied to pulverized coal boilers in which pulverized coal burners are provided in the furnace of the pulverized coal boiler and after-air ports are also provided downstream of the burners, as disclosed in Japanese Patent Laid-open No. Hei 6(1994)-201105 ; pulverized coal used as a fuel and combustion air is supplied from the burners, and combustion air is supplied from the after-air ports.
  • combustion air is supplied from the burners by an amount by which the theoretical stoichiometric ratio necessary for complete combustion of the pulverized coal used as a fuel is not exceeded, the combustion air being supplied together with the pulverized coal as a fuel gas; the pulverized coal included in the fuel gas is burnt in a state in which air is insufficient in the furnace so that a reducing atmosphere is created, and NOx generated during the combustion is reduced to nitrogen to suppress the generation of NOx.
  • unburnt pulverized coal is left in the fuel gas supplied from the burners into the furnace due to the oxygen insufficiency, generating CO (carbon monoxide).
  • CO carbon monoxide
  • combustion air is supplied from the after-air ports located downstream of the burners to the furnace by an amount a little more than the amount of air equivalent to an insufficiency relative to the theoretical stoichiometric ratio, so that the unburnt pulverized coal and CO are burnt to reduce the generation of NOx and CO.
  • the combustion gas resulting from the combustion of the pulverized coal included in the fuel is directed down in the furnace so that the combustion gas exchanges heat with a heat exchanger (not shown) installed in the furnace to extract heat from the combustion gas; the combustion gas is then cooled and expelled from the furnace to the outside of the pulverized coal boiler as an exhaust gas.
  • a heat exchanger not shown
  • NOx gases generated in boilers are broadly classified into fuel NOx and thermal NOx.
  • Fuel NOx is generated when nitrogen compounds included in coal used as a fuel are oxidized. This type of fuel NOx is substantially reduced by improved technologies applied to combustion in burners.
  • Thermal NOx is generated when nitrogen included in the air is oxidized at high temperature.
  • thermal NOx As fuel NOx has been reduced, the amount of thermal NOx generated can be no longer neglected in recent years. To further reduce NOx, thermal NOx must be reduced.
  • the spray nozzle Since it is also necessary to have the spray nozzle include the driving unit for retracting and inserting the spray nozzle through which water or steam is supplied, the structure of the spray nozzle becomes complex, increasing costs for the maintenance and other services for the unit. It is also conceivable in terms of reliability that if the spray nozzle is kept inserted into the inside of the furnace for a long period of time, the spray nozzle may not withstand prolonged use due to ash adhering to the spray nozzle and structural member deformation caused by a contact with the combustion gas at high temperature.
  • An object of the present invention is to provide a highly reliable pulverized coal boiler that ensures suppression of a rise in flame temperature caused during the combustion of an unburnt gas in a furnace when combustion air is supplied from after-air ports so as to reduce the concentration of thermal NOx generated during the combustion.
  • a pulverized coal boiler comprising a furnace, a burner provided on a wall of the furnace for supplying pulverized coal to the inside of the furnace and burning the pulverized coal, and an after-air port provided on the wall of the furnace at a position downstream of the burner for supplying combustion air to the inside of the furnace, wherein a plurality of after-air ports are disposed in the furnace in a combustion gas flow-direction; and at least one of the plurality of after-air ports disposed upstream in the combustion gas flow direction in the furnace supplies the water, the steam, or the two fluids including water and steam to the inside of the furnace.
  • the spray nozzle 6 which is a single-fluid nozzle, is disposed on the after-air port 3.
  • the pulverized coal boiler 100 in FIG. 1 has a furnace 1, on the wall of which a plurality of burners 2 are disposed; a fuel gas, in which pulverized coal used as a fuel and combustion air are mixed, is supplied from the plurality of burners 2.
  • a plurality of after-air ports 3 are provided at positions downstream of the burners 2 on the wall of the furnace 1.
  • Coal used as a fuel in the pulverized coal boiler 100 is crushed into powder by a plurality of mills 7, resulting in pulverized coal.
  • the pulverized coal is then supplied through pipes 7b to the burners 2, and further supplied from the burners 2 to the inside of the furnace 1 together with combustion air supplied by a blower 12 through a duct pipe 14, as a fuel gas, and the fuel gas is burnt therein.
  • Part of the hot air resulting from the heat exchange is adjusted for the amount to be apportioned by dampers 8 disposed at intermediate points on the duct pipe 14.
  • the apportioned air is supplied to each wind box 4, which is provided on the wall of the furnace 1 and internally includes burners 2, and further supplied from the wind box 4 to the inside of the furnace 1 as outer circumferential air of the burners 2.
  • the apportioned air is supplied to a wind box 5, which is provided on the wall of the furnace 1 and internally includes the after-air port 3, and further supplied from the wind box 5 through the after-air port 3 to the inside of the furnace 1 as the combustion air, as described above.
  • a combustion gas 10 resulting from the combustion of the pulverized coal included in the furnace 1 flows in the furnace 1 toward the downstream side and is exhausted through a pipe 14b to the outside of the furnace 1, as an exhaust gas 11. Since the heat exchanger 13 is disposed in the pipe 14b, a heat exchange occurs in the heat exchanger 13 between the exhaust gas 11 and the combustion air. Denitrification and desulfurization (not shown) are then performed for the combustion air, after which the exhaust gas 11 is released from a chimney 15 with which the pipe 14b connects.
  • the spray nozzle 6 is disposed in the after-air port 3 provided on the wall of the furnace 1.
  • Water 18, which is a cooling fluid for suppressing the generation of thermal NOx during the combustion of the combustion gas, is supplied from a pump 16 through a pipe 42 to the spray nozzle 6.
  • the flow rate of the water 18 (cooling fluid) to be sprayed from the spray nozzle 6 toward the inside of the furnace 1 is adjusted based on the NOx concentration of the exhaust gas 11, the NOx concentration being detected by a NOx detector 55 provided in the pipe 14b though which the exhaust gas 11 from the furnace 1 is exhausted to the outside.
  • a NOx concentration signal about the exhaust gas 11 detected by the NOx detector 55 is input to a controller 50.
  • the controller 50 compares the NOx concentration with a desired NOx setting, calculates a flow rate command signal about the cooling fluid to be sprayed from the spray nozzles 6 toward the inside of the furnace 1 so that the NOx concentration of the exhaust gas 11 is maintained at the desired setting, and outputs the command signal to a valve 17 used for flow rate adjustment, which is provided in a pipe 42, through which the water 18 (cooling fluid) is supplied to the spray nozzles 6.
  • the opening of the valve 17 is adjusted in response to the flow rate command signal calculated by the controller 50 to raise the flow rate of the water 18 (cooling fluid) to be supplied from the spray nozzles 6, so that a rise in the flame temperature is suppressed and NOx is reduced.
  • the opening of the valve 17 is adjusted in response to the flow rate command signal calculated by the controller 50 to lower the flow rate of the water 18 (cooling fluid) or the supply of the water 18 is stopped, so that an appropriate amount of water is sprayed from the spray nozzle 6 and an efficient operation is performed.
  • the flow rate of the water 18 (cooling fluid) to be sprayed from the spray nozzles 6 toward the inside of the furnace 1 may be controlled based on the load of the pulverized coal boiler 100.
  • the load of the pulverized coal boiler 100 is structured so that the flow rate of the water 18 (cooling fluid) to be sprayed from the spray nozzles 6 toward the inside of the furnace 1 is adjusted based on a boiler load signal commanded from a control room.
  • the boiler load signal commanded from the control room is entered to the controller 50, and then the controller 50 calculates a flow rate command signal about the cooling fluid to be sprayed from the spray nozzles 6 toward the inside of the furnace 1.
  • the command signal is output from the controller 50 to the valve 17, used for flow rate adjustment, which is disposed on the pipe 42 for supplying the cooling fluid to the spray nozzles 6 so that the flow rate of the cooling fluid is adjusted.
  • the flow rate of the water 18 (cooling fluid) to be sprayed from the spray nozzles 6 is adjusted so that if the load of the pulverized coal boiler 100 is low, the opening of the valve 17 is adjusted to lower the flow rate of the water 18, or if the load is high, the opening is adjusted to raise the flow rate of the water 18. Then, it becomes possible to spray an appropriate amount of cooling fluid and perform an efficient operation.
  • FIG. 15 is a block diagram showing the structure of the controller 50.
  • the controller 50 includes a spray amount calculator 53 to which the boiler load signal and the NOx detection value of the exhaust gas 11, which is detected by the NOx detector 55, are input.
  • the controller 50 also includes a boiler load setting unit 51 for setting an operation load for the boiler and a NOx concentration setting unit 52 for setting a NOx concentration.
  • the spray amount calculator 53 in the controller 50 compares the boiler load signal with the load setting (threshold) in the boiler load setting unit 51. If the detected value exceeds the setting, the spray amount calculator 53 calculates the flow rate of the water 18 (cooling fluid) that corresponds to the difference between the setting and detected value, and outputs an opening of the valve 17, which corresponds to the calculated spray amount, to the valve 17 as a command signal so that the flow rate of the water 18 to be sprayed from the spray nozzles 6 toward the inside of the furnace 1 is adjusted.
  • FIGs. 16A and 16B are graphs indicating characteristics for controlling the valve that adjusts the flow rate of the cooling fluid.
  • the vertical axis indicates the detected NOx concentration of the exhaust gas 11
  • the horizontal axis indicates the opening of the valve 17
  • the dashed line indicates a setting and the solid line indicates opening characteristics of the valve 17 with respect to the detected NOx concentration.
  • the vertical axis indicates the boiler load and the horizontal axis indicates the opening of the valve 17, while the dashed line indicates a setting and the solid line indicates the opening characteristics of the valve 17 with respect to the boiler load.
  • the opening of the valve 17 is set to 0 (closed) to stop the water from being sprayed from the spray nozzles 6. If the value of the detected NOx concentration exceeds the setting, the valve 17 is opened based on the opening of the valve 17, which corresponds to a calculated spray amount based on a difference from the setting, so that the spray of the water from the spray nozzles 6 is controlled.
  • FIG. 2 is an enlarged view showing part of the structure of the after-air port 3, which has a spray nozzle, the after-air port 3 being used in the pulverized coal boiler, shown in FIG. 1 , in this embodiment of the present invention.
  • the after-air port 3 in this embodiment is provided on the wind box 5 at one end; at the other end, the after-air port 3 has a straight flow path 30, which is cylindrical and communicates with an opening 3a of the after-air port 3, which is formed in the wall of the furnace 1.
  • the after-air port 3 also has a swirl flow path 31, which has a truncated cone shape, on the outer circumference of the straight flow path 30; an end of the swirl flow path 31 is connected to the wall of the furnace 1, forming an external edge of the opening 3a of the after-air port 3.
  • a swirl flow 36 which is also part of the combustion air, is adjusted for its swirl intensity by means of a register 32 provided in the swirl flow path 31, which has a truncated cone shape and is formed around the outer circumference of the straight flow path 30, and supplied from the opening at the end of the swirl flow path 31 to the inside of the furnace 1.
  • a jet flow 40 of combustion air is formed in the inside of the furnace 1, the inside communicating with the opening 3a of the after-air port 3; the jet flow 40 spreads from the opening 3a toward the center of the furnace 1, as shown in FIG. 2 , by the combustion air supplied from the straight flow path 30 and swirl flow path 31 formed in the after-air port 3.
  • the unburnt gas 10a is burnt as a result of mixing the combustion air supplied as the jet flow 40 and the unburnt gas 10a; when the temperature of a generated flame rises, thermal NOx is generated.
  • the latent heat and sensible heat of the water 18 sprayed in the spray area 18a overlapping the mixed area 41 deprive the heat of the flame resulting from the combustion of the unburnt gas 10a in the mixed area 41, suppressing the flame temperature from rising.
  • the generation of thermal NOx can then be reduced in the mixed area 41 in which thermal NOx is most easily generated.
  • the spray nozzle 6 in this embodiment is disposed near the opening 3a of the after-air port 3, it becomes possible to prevent ash from adhering to the spray nozzle and the structural members from being deformed due to contact with the combustion gas at high temperature and thereby obtain a highly reliable spray nozzle that can withstand prolonged use.
  • FIG. 3 shows the opening 3a of the after-air port 3 having the spray nozzle 6, as viewed along line A-A in FIG. 2 .
  • the water 18 (cooling fluid) is sprayed so that it spreads concentrically from the spray nozzle 6, as one form of the spray range 18a overlapping the mixed area 41, where the jet flow 40 of combustion air supplied from the opening 3a of the after-air port 3 shown in FIG. 2 is mixed with the unburnt gas 10a.
  • FIGs. 5 and 6 show part of the structure of an after-air port in another embodiment that is used in the pulverized coal boiler shown in FIG. 1 , which embodies the present invention.
  • the basic structure of the after-air port 3 in this embodiment shown in FIGs. 5 and 6 is the same as the basic structure of the after-air port 3 in the embodiment shown in FIGs. 2 to 4 , so the explanation of the same basic structure will be omitted and only different parts will be described.
  • each spray nozzle 6 for spraying water is positioned near the opening 3a of the after-air port 3, as in the structure of the after-air port 3 shown in the embodiment shown in FIG. 2 .
  • the water 18 (cooling fluid) can be precisely sprayed from the spray nozzles 6 in the spray range 18a overlapping the mixed area 41, where the jet flow 40 of combustion air and the unburnt gas 10a are mixed, the jet flow 40 being jetted from the after-air port 3 to the inside of the furnace 1, the inside communicating with the opening 3a of the after-air port 3.
  • FIGs. 7 and 8 show part of the structure of an after-air port in other embodiment that is used in the pulverized coal boiler shown in FIG. 1 , which embodies the present invention.
  • FIG. 7 shows the structure of the after-air port, having spray nozzles, in the other embodiment.
  • FIG. 8 shows a section as viewed along line C-C in FIG. 7 .
  • a pulverized coal boiler in which the after-air port 3 in this embodiment is used has the same structure as the pulverized coal boiler 100 in the embodiment shown in FIG. 1 , so the explanation of the pulverized coal boiler including the after-air port 3 in this embodiment will be omitted.
  • the spray nozzles 6 in this embodiment are also disposed near the opening 3a of the after-air port 3, it becomes possible to prevent ash from adhering to the spray nozzles and the structural members from being deformed due to contact with the combustion gas at high temperature. Furthermore, since a plurality of spray nozzle are provided, even if some of the plurality of spray nozzles are clogged, a necessary amount of cooling fluid can still be sprayed by the remaining spray nozzles, so it becomes possible to obtain highly reliable spray nozzles that can withstand prolonged use.
  • the basic structure of the after-air ports 3 in this embodiment shown in FIGs. 9 and 10 are the same as the basic structure of the after-air ports 3 in the embodiments shown in FIGs. 5 and 7 , so the explanation of the same basic structure will be omitted and only different parts will be described.
  • each spray nozzle 6, included in the after-air port 3 in each embodiment, from which the water 18 (cooling fluid) is sprayed, is disposed so that the end of the spray nozzle 6 is positioned near the wall of the wind box 5 rather than the opening 3a of the after-air port 3 to leave a distance from the furnace 1; the end of the spray nozzle 6 is located, in the after-air port 3, at an upstream position of the jet flow 40 of combustion air, relative to the opening 3a of the after-air port 3.
  • the water 18 (cooling fluid) is sprayed from each spray nozzle 6 at an upstream position of the jet flow 40 of combustion air supplied from the opening 3a of the after-air port 3 into the inside of the furnace 1, and vaporized so that moisture is further evenly mixed with the jet flow 40 of combustion air supplied from the after-air port 3, adding the moisture to the jet flow 40 itself of the combustion air supplied from the after-air port 3. Accordingly, the moisture can be more precisely supplied to the spray range 18a overlapping the mixed area 41, where the jet flow 40 and the unburnt gas 10a are mixed, and thereby a rise in flame temperature can be more surely suppressed.
  • control of the cooling fluid by the spray nozzles 6 in the after-air ports 3 in this embodiment, shown in FIGs. 9 and 10 can be carried out by having the controller 50 adjust the flow rate of the cooling fluid as in the embodiments described above.
  • the above embodiments in the present invention can also achieve a highly reliable pulverized coal boiler that ensures suppression of a flame temperature rise that is caused during the combustion of an unburnt gas in a furnace when combustion air is supplied from after-air ports so as to reduce the concentration of thermal NOx generated during the combustion.
  • a two-fluid nozzle which can spray two fluids including water 18 and steam 20 is used as the spray nozzle 6 disposed in the after-air port 3.
  • a system for supplying the water 18 to the spray nozzles 6, each of which sprays the two fluids including water 18 and steam 20 as the cooling fluid uses the same the pipe 42 and the valve 17 as shown in FIG. 1 .
  • a system for supplying the steam 20 to the spray nozzles 6, each of which sprays the two fluids, has a steam tank 21 to which part of steam used in a power generation plant is supplied for storage purposes, the pressure in the steam tank 21 being set to a prescribed value.
  • the system also has a pipe 43 through which the steam 20 stored in the steam tank 21 is supplied to the spray nozzles 6, a valve 22 for adjusting the flow rate of the steam 20 supplied is provided on the pipe 43.
  • the opening of the valve 22, which adjusts the flow rate of the steam 20 sprayed from the two-fluid spray nozzles 6 into the inside of the furnace 1, is controlled by the controller 50.
  • the spray amount calculator 53 in the controller 50 compares a boiler load and the NOx emission concentration of the exhaust gas 11, which is detected by the NOx detector 55, with the setting in the boiler load setting unit 51 and the setting in the NOx concentration setting unit 52, respectively. Then, the spray amount calculator 53 calculates the amount of the steam 20 that needs to be supplied.
  • the opening of the valve 22 that corresponds to the amount of steam is commanded as an opening signal by the spray amount calculator 53 in the controller 50 for the valve 22 so that the necessary amount of steam 20 is sprayed from the spray nozzles 6.
  • the opening of the valve 22 is controlled by the controller 50 in the same way as the opening of the valve 17 is controlled by the controller 50 as shown in FIGs. 16A and 16B .
  • the above embodiment in the present invention can also achieve a highly reliable pulverized coal boiler that ensures suppression of a flame temperature rise that is caused during the combustion of an unburnt gas in a furnace when combustion air is supplied from after-air ports so as to reduce the concentration of thermal NOx generated during the combustion.
  • the basic structure of the pulverized coal boiler in this embodiment is the same as the basic structure of the pulverized coal boiler 100 in the embodiment shown in FIG. 1 , so the explanation of the same basic structure will be omitted and only different parts will be described.
  • the jet flow 40 of combustion air with which the water 18 (cooling fluid) sprayed from the spray nozzle 6 into the wind box 5 and vaporized is mixed, can be precisely and evenly sprayed in the mixed area 41, where the jet flow 40 of combustion air and the unburnt gas 10a are mixed, the jet flow 40 being jetted toward the inside of the furnace 1, the inside communicating with the opening 3a of the after-air port 3.
  • the latent heat and sensible heat of the water 18 sprayed from the spray nozzle 6 deprive the heat of the flame resulting from the combustion of the unburnt gas 10a in the mixed area 41, so it is possible to suppress the flame temperature to about 1600K or below, preferably about 1600K to about 1400K.
  • the concentration of NOx generated in the boiler can thereby be reduced by about 10% to 30%.
  • FIG. 17 is a schematic diagram indicating the structure of a pulverized coal boiler 100 in other embodiment of the present invention.
  • the pulverized coal boiler 100 comprises burners 2 for burning pulverized coal used as a fuel, after-air ports 3 for supplying combustion air, and spray nozzles 6 for spraying water (cooling fluid) into a duct pipe 14 through which the combustion air is supplied to the after-air ports 3.
  • the basic structure of the pulverized coal boiler in this embodiment is the same as the basic structure of the pulverized coal boiler 100 in the embodiment shown in FIG. 1 , so the explanation of the same basic structure will be omitted and only different parts will be described.
  • the ratio of the vaporization of the water 18 sprayed from the spray nozzle 6 is increased and lessens drainage water, and thereby the water 18 (cooling fluid) sprayed from the spray nozzle 6 is more efficiently vaporized.
  • the steam 20 or two fluids including the water and steam may be sprayed instead of the water.
  • control of the cooling fluid by the spray nozzles 6 disposed in the wind boxes 5 in this embodiment can be carried out by having the controller 50 adjust the flow rate of the cooling fluid as in the embodiments described above.
  • the basic structure of the pulverized coal boiler in this embodiment is the same as the basic structure of the pulverized coal boiler 100 in the embodiment shown in FIG. 17 , so the explanation of the same basic structure will be omitted and only different parts will be described.
  • the sub after-air ports 60 are disposed in the direction in which the combustion gas 10 flows in the furnace 1 on the upstream side and main after-air ports 61 are disposed on the downstream side.
  • the sub-after port 60 has the spray nozzle 6, from which water or both water and steam is sprayed.
  • the amount of air supplied from the sub after-air port 60 is smaller than the amount of air supplied from the main after-air port 61.
  • the air flows 62 supplied from the sub-after ports 60 into the inside of the furnace 1 by being sprayed are directed toward the downstream side along the inner wall of the furnace 1 because the amount of air sprayed is small.
  • the combustion gas 10a While flowing from downstream to upstream in the furnace 1, the combustion gas 10a is mixed with the air flows 62 and 63. Near the wall of the furnace 1, the temperature of the combustion gas 10a mixed with the air flow 62 on the upstream side is higher than the temperature of the combustion gas 10a mixed with the air flow 63 on the downstream side.
  • the pulverized coal boiler 100 in this embodiment is structured so that water is sprayed from the spray nozzles 6 disposed in the sub after-air ports 60 on the upstream side, the air flow 62 includes much moisture supplied from the sub after-air port 60 toward the inside of the furnace 1.
  • part of the air flow 62 is further mixed with the air flow 63 jetted from the main after-air port 61 located downstream of the air flow 62.
  • part of the air flow 62 including moisture is mixed with the air flow 63, part of a gas already burnt in an inner wall vicinity 64 in the furnace 1 is involved in the air flow 63 jetted from the main after-air port 61, so a burnt gas including moisture flows along the outermost circumference of the air flow 63.
  • the combustion temperature can be reduced due to the specific heats of the moisture included in the burnt gas.
  • the amount of thermal NOx generated at the central part of the furnace 1 can be reduced.
  • the air flow jetted from the after air port and the combustion gas 10a are mixed, as described above, the air flow including much moisture and the burnt gas including moisture are supplied to the inner wall vicinity 64 in the furnace 1 in a relatively upstream region, the central part 65 of the furnace 1, and other parts where high temperature is easily reached, enabling the amount of thermal NOx generated to be suppressed to a small value.
  • thermal efficiency is lowered by the supplied water, since thermal NOx is suppressed, it is possible to suppress, at a downstream site of the furnace 1, power for operating units to reduce NOx and the amount of chemicals supplied.
  • the steam 20 or two fluids including water 18 and steam 20 may be sprayed instead of water 18.
  • the swirl flow causes much of the water 18 jetted from the spray nozzle 6 to flow around the outer circumference of the air flow 62, so much moisture is included in the mixture of the combustion gas 10a and the air flow 62. Accordingly, the concentration of the thermal NOx can be reduced with a small amount of water.
  • the cooling fluid sprayed from the spray nozzle 6 disposed in the sub after-air port 60 is controlled by the controller 50, as in the embodiments described above.
  • a NOx concentration signal about the exhaust gas 11 detected by the NOx detector 55 is entered to the controller 50.
  • the controller 50 compares the NOx concentration with a desired NOx setting, calculates a flow rate command signal about the cooling fluid to be sprayed from the spray nozzles 6 toward the inside of the furnace 1 so that the NOx concentration of the exhaust gas 11 is maintained at the desired setting, and outputs the command signal to the valve 17 used for flow rate adjustment, which is disposed in the pipe 42, through which the water 18 (cooling fluid) is supplied to the spray nozzles 6.
  • This arrangement enables the flow rate of the cooling fluid to be appropriately controlled and thereby the thermal NOx concentration to be reduced.
  • the pulverized coal boiler 100 described above can be a highly reliable pulverized coal boiler that ensures suppression of a flame temperature rise that is caused during the combustion of an unburnt gas in a furnace when combustion air is supplied from after-air ports so as to reduce the concentration of thermal NOx generated during the combustion.
  • the present invention can be applied to a pulverized coal boiler that uses pulverized coal as a fuel, more particularly to a pulverized coal boiler that suppresses the generation of thermal nitrogen oxides.
  • the present invention can also be applied to conventional pulverized boilers with ease.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Supply (AREA)
EP07831257A 2006-11-08 2007-11-06 Kohlenstaubkessel Withdrawn EP2083216A4 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2006302881 2006-11-08
PCT/JP2007/071525 WO2008056650A1 (en) 2006-11-08 2007-11-06 Pulverized coal boiler

Publications (2)

Publication Number Publication Date
EP2083216A1 true EP2083216A1 (de) 2009-07-29
EP2083216A4 EP2083216A4 (de) 2013-03-06

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EP07831257A Withdrawn EP2083216A4 (de) 2006-11-08 2007-11-06 Kohlenstaubkessel

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Country Link
US (1) US20100031858A1 (de)
EP (1) EP2083216A4 (de)
JP (1) JP5095628B2 (de)
WO (1) WO2008056650A1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104089299A (zh) * 2014-07-08 2014-10-08 北京科电瑞通科技股份有限公司 低氮燃烧方法
CN104089279A (zh) * 2014-07-08 2014-10-08 北京科电瑞通科技股份有限公司 低氮燃烧系统
CN105003912A (zh) * 2015-07-24 2015-10-28 湖南高华环保股份有限公司 低NOx燃烧方法以及低NOx燃烧系统

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080156236A1 (en) * 2006-12-20 2008-07-03 Osamu Ito Pulverized coal combustion boiler
CN102016415B (zh) * 2008-03-06 2012-08-15 株式会社Ihi 氧燃烧锅炉的二氧化碳供给方法以及二氧化碳供给设备
US8327779B2 (en) 2008-09-26 2012-12-11 Air Products And Chemicals, Inc. Combustion system with steam or water injection
BRPI1014209A2 (pt) * 2009-03-26 2016-04-05 Fadi Eldabbagh "sistema para reduzir emissões e melhorar eficiência de energia em sistemas de combustão de combustíveis fósseis e biocombustíveis."
JP5417258B2 (ja) * 2010-06-01 2014-02-12 バブコック日立株式会社 噴霧ノズルを備えた燃焼装置
US8703064B2 (en) 2011-04-08 2014-04-22 Wpt Llc Hydrocabon cracking furnace with steam addition to lower mono-nitrogen oxide emissions
CN103047672B (zh) * 2012-12-18 2015-05-20 华中科技大学 一种过热蒸汽煤粉燃烧装置
CN104896501B (zh) * 2015-06-05 2016-04-20 华中科技大学 一种煤粉低NOx富氧燃烧装置
JP6242453B1 (ja) * 2016-08-25 2017-12-06 中外炉工業株式会社 加熱炉の冷却装置
US11366089B2 (en) * 2018-03-14 2022-06-21 Mitsubishi Heavy Industries, Ltd. Analysis condition adjusting device of simple fuel analyzer
JP6701258B2 (ja) * 2018-03-14 2020-05-27 三菱重工業株式会社 燃料簡易分析装置及びその分析条件調整装置
GB2576044B (en) * 2018-08-03 2021-05-26 Spirax Sarco Ltd Calibration of a boiler
CN109269864B (zh) * 2018-12-11 2024-09-13 长沙开元仪器有限公司 一种煤样制粉设备
CN111256109B (zh) * 2020-02-20 2022-02-22 苏州西热节能环保技术有限公司 一种缓解对冲燃煤锅炉管壁温度偏差的方法
CN111392262B (zh) * 2020-04-20 2024-09-10 西安热工研究院有限公司 一种配置气力疏松装置的电站锅炉双燃料原煤仓系统
CN115371043A (zh) * 2021-05-21 2022-11-22 上海梅山钢铁股份有限公司 一种基于锅炉ct技术的燃烧优化控制方法
JP7460096B1 (ja) 2023-01-18 2024-04-02 株式会社プランテック 竪型ごみ焼却炉及び竪型ごみ焼却炉の燃焼方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5915310A (en) * 1995-07-27 1999-06-29 Consolidated Natural Gas Service Company Apparatus and method for NOx reduction by selective injection of natural gas jets in flue gas
US20060115779A1 (en) * 2004-11-04 2006-06-01 Babcock-Hitachi K.K. Overfiring air port, method for manufacturing air port, boiler, boiler facility, method for operating boiler facility and method for improving boiler facility
JP2007139266A (ja) * 2005-11-16 2007-06-07 Babcock Hitachi Kk ボイラ装置とその運転方法

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5112423A (ja) * 1974-07-23 1976-01-31 Nippon Kokan Kk Baana
CH585370A5 (de) * 1975-04-29 1977-02-28 Von Roll Ag
CH583881A5 (de) * 1975-07-04 1977-01-14 Von Roll Ag
JPS5292134A (en) * 1976-01-30 1977-08-03 Mitsubishi Heavy Ind Ltd Boiler
JPS58208508A (ja) * 1982-05-27 1983-12-05 Mitsubishi Heavy Ind Ltd ボイラのＮＯｘ抑制方法
JPS59131803A (ja) * 1983-01-17 1984-07-28 Hitachi Ltd 蒸気噴射制御方式
JP2954643B2 (ja) * 1990-04-03 1999-09-27 バブコツク日立株式会社 ボイラ装置
US5195450A (en) * 1990-10-31 1993-03-23 Combustion Engineering, Inc. Advanced overfire air system for NOx control
JP3308618B2 (ja) 1993-01-07 2002-07-29 バブコック日立株式会社 低ＮＯｘ燃焼方法と装置
US5543116A (en) * 1994-07-15 1996-08-06 The Babcock & Wilcox Company Method for reducing NOx using atomizing steam injection control
US5832846A (en) * 1996-01-11 1998-11-10 Public Service Electric And Gas Corporation Water injection NOx control process and apparatus for cyclone boilers
JP3915951B2 (ja) * 1998-04-21 2007-05-16 バブコック日立株式会社 ボイラ燃焼装置
JP2003322310A (ja) 2002-04-24 2003-11-14 Ishikawajima Harima Heavy Ind Co Ltd ボイラＮＯｘ低減装置
US7270539B1 (en) * 2003-10-28 2007-09-18 Soil-Therm Equipment, Inc. Method and apparatus for destruction of vapors and waste streams using flash oxidation
JP4444791B2 (ja) * 2004-11-04 2010-03-31 バブコック日立株式会社 燃料燃焼用空気ポート、その製造方法及びボイラ

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5915310A (en) * 1995-07-27 1999-06-29 Consolidated Natural Gas Service Company Apparatus and method for NOx reduction by selective injection of natural gas jets in flue gas
US20060115779A1 (en) * 2004-11-04 2006-06-01 Babcock-Hitachi K.K. Overfiring air port, method for manufacturing air port, boiler, boiler facility, method for operating boiler facility and method for improving boiler facility
JP2007139266A (ja) * 2005-11-16 2007-06-07 Babcock Hitachi Kk ボイラ装置とその運転方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2008056650A1 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104089299A (zh) * 2014-07-08 2014-10-08 北京科电瑞通科技股份有限公司 低氮燃烧方法
CN104089279A (zh) * 2014-07-08 2014-10-08 北京科电瑞通科技股份有限公司 低氮燃烧系统
CN104089279B (zh) * 2014-07-08 2016-08-17 北京科电瑞通科技股份有限公司 低氮燃烧系统
CN104089299B (zh) * 2014-07-08 2016-11-09 北京科电瑞通科技股份有限公司 低氮燃烧方法
CN105003912A (zh) * 2015-07-24 2015-10-28 湖南高华环保股份有限公司 低NOx燃烧方法以及低NOx燃烧系统
CN105003912B (zh) * 2015-07-24 2017-10-27 湖南高华环保股份有限公司 低NOx燃烧方法以及低NOx燃烧系统

Also Published As

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JPWO2008056650A1 (ja) 2010-02-25
JP5095628B2 (ja) 2012-12-12
EP2083216A4 (de) 2013-03-06
US20100031858A1 (en) 2010-02-11
WO2008056650A1 (en) 2008-05-15

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