EP0460160B1 - Process for reducing nox emission during the combustion of solid fuels - Google Patents

Process for reducing nox emission during the combustion of solid fuels Download PDF

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Publication number
EP0460160B1
EP0460160B1 EP91901273A EP91901273A EP0460160B1 EP 0460160 B1 EP0460160 B1 EP 0460160B1 EP 91901273 A EP91901273 A EP 91901273A EP 91901273 A EP91901273 A EP 91901273A EP 0460160 B1 EP0460160 B1 EP 0460160B1
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Prior art keywords
reduction
zone
reduction zone
combustion
fuel
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EP91901273A
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German (de)
French (fr)
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EP0460160A1 (en
Inventor
Heinz Spliethoff
Hartmut Spliethoff
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Saarbergwerke AG
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Saarbergwerke AG
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Priority to AT91901273T priority Critical patent/ATE88257T1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C6/00—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion
    • F23C6/04—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection
    • F23C6/045—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection with staged combustion in a single enclosure
    • F23C6/047—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection with staged combustion in a single enclosure with fuel supply in stages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J7/00—Arrangement of devices for supplying chemicals to fire
    • 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 
    • F23C2201/00—Staged combustion
    • F23C2201/10—Furnace staging
    • F23C2201/101—Furnace staging in vertical direction, e.g. alternating lean and rich zones
    • 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 
    • F23C2201/00—Staged combustion
    • F23C2201/30—Staged fuel supply
    • F23C2201/301—Staged fuel supply with different fuels in stages

Definitions

  • the invention relates to a method for reducing nitrogen oxide emissions during the firing of solid fuels, in particular hard coal, wherein reducing fuel is added and burnt to the flue gases withdrawing from a main firing zone.
  • reducing fuel is added and burnt to the flue gases withdrawing from a main firing zone.
  • the nitrogen oxide emission from combustion plants operated with solid fuels can be influenced both by suitable control of the combustion process, so-called primary measures, and by treatment of the flue gases withdrawn from the furnace, so-called secondary measures.
  • the secondary measures aim to remove nitrogen oxides from the flue gases that are extracted from the furnace.
  • Another, comparatively simple way of reducing the nitrogen oxide emission is to add additional reduction fuel to the flue gases withdrawing from the main combustion zone of a furnace and to burn them in a so-called reduction zone.
  • this measure alone is usually not sufficient to be able to comply with the legally prescribed emission limit values for nitrogen oxides, so that usually additional secondary measures, such as e.g. catalytic denitrification cannot be dispensed with.
  • the object of the invention is therefore to improve this method of the type described above, so that high degrees of denitrification can be achieved in a simple and economical manner.
  • This object is achieved in that the flue gases flow through two reduction zones in succession, that the first reduction zone is operated sub-stoichiometrically at temperatures above 1,000 ° C and with the addition of a reduction fuel and that the second reduction zone is over-stoichiometric in the presence of nitrogen oxide-reducing substances at temperatures of 950 ° C is operated up to 1,000 ° C.
  • Ammonia, ammonia water, urea solutions or the like are mainly used as nitrogen oxide reducing substances. used.
  • the combination of nitrogen oxide reduction by reducing fuel in a substoichiometric reduction zone and by nitrogen oxide reducing substances in a superstoichiometric reduction zone according to the invention significantly improves the degree of denitrification.
  • the nitrogen-reducing substances are expediently added, at least partially, together with the reduction fuel to the first reduction zone.
  • the nitrogen oxide reduction is further increased significantly in the first reduction zone, since in the substoichiometric atmosphere there the nitrogen oxide reducing substances also have a reducing effect even at high temperatures above 1,000 ° C.
  • the residence time of the flue gases in this first reduction zone should expediently be at least 0.1 s.
  • the nitrogen oxide-reducing substances then further reduce the nitrogen oxide, although a temperature range of 950 ° C. to 1,000 ° C. must be maintained due to the stoichiometric conditions.
  • the setting of the superstoichiometric conditions in the second reduction stage is expediently carried out by adding an excess amount of burnout air beyond what is required to completely burn out the reduction amount.
  • the narrow temperature range to be maintained under superstoichiometric conditions can be maintained simply and precisely via the amount and temperature of the combustion air supplied. Since the nitrogen oxide-reducing substances are already mixed in the first reduction zone, it is ensured that they are distributed evenly in the flue gas through the temperature range to be observed for the nitrogen oxide reduction.
  • the method according to the invention is further explained on the basis of a melting chamber firing shown by way of example in the figure.
  • a firing system 1 has a main firing zone 2 with burners 10 and a fuel feed 7.
  • the flue gases of the main firing zone 2 are deflected by 180 ° in the example of a smelting chamber firing and passed through a grate 4.
  • the redirected flue gas stream then flows through two reduction zones 6 and 9 in succession.
  • reduction fuel is fed in via line 5 and nitrogen oxide-reducing substances metered in via line 3 into the flue gas stream and mixed with it .
  • the introduction can also take place at a plurality of inlet points distributed around the circumference of the reduction zone 6.
  • flue gas can additionally be recirculated via line 11.
  • the flow length of the first reduction zone 6 is sufficiently large to ensure that the flue gases remain in this reduction zone 6 for at least 0.1 s.
  • a sufficiently large amount of burnout air is added to the flue gas via line 7 at the end of the first reduction zone 6, which ensures that overstoichiometric conditions are present in the second reduction zone 9, with the amount and temperature of the added burnout air also required for the nitrogen oxide reduction in the overstoichiometric atmosphere
  • Temperature range from 950 ° C to 1,000 ° C is set.
  • Additional nitrogen oxide-reducing substances can be metered in via line 8, because of the better mixing, expediently together with the burnout air and possibly also here returned flue gas via line 12, the ratio of recirculated flue gas to fresh air being limited by the conditions after an over-stoichiometric atmosphere.
  • the introduction can take place at a plurality of inlet points arranged distributed around the circumference of the second reduction zone 9.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Treating Waste Gases (AREA)
  • Catalysts (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)

Abstract

PCT No. PCT/DE90/00985 Sec. 371 Date Aug. 26, 1991 Sec. 102(e) Date Aug. 26, 1991 PCT Filed Dec. 21, 1990 PCT Pub. No. WO91/10097 PCT Pub. Date Jul. 11, 1991.In a process for reducing the nitric oxide emission during the combustion of solid fuels, the flue gases leaving from a main combustion zone (2) consecutively flow through two reduction zones (6,9). The first reduction zone (6) is operated hypostoichiometrically at temperatures above 1,000 DEG C. and while adding a reducing fuel, while the second reduction zone (9) is operated hyperstoichiometrically at temperatures from 950 DEG C. to 1,000 DEG C. and in the presence of nitric oxide-reducing substances.

Description

Die Erfindung betrifft ein Verfahren zur Verringerung der Stickoxidemission bei der Verfeuerung von festen Brennstoffen, insbesondere von Steinkohlen, wobei den aus einer Hauptfeuerungszone abziehenden Rauchgasen Reduktionsbrennstoff zugegeben und verbrannt wird. Ein solches Verfahren ist aus Dokument EP-A- 0 159 492 bekannt.The invention relates to a method for reducing nitrogen oxide emissions during the firing of solid fuels, in particular hard coal, wherein reducing fuel is added and burnt to the flue gases withdrawing from a main firing zone. Such a method is known from document EP-A-0 159 492.

Die Stickoxidemission von mit Festbrennstoffen betriebenen Feuerungsanlagen kann sowohl durch geeignete Führung des Verbrennungsprozesses, sog. Primärmaßnahmen, als auch durch Behandlung der aus der Feuerung abziehenden Rauchgase, sog. Sekundärmaßnahmen, beeinflußt werden.The nitrogen oxide emission from combustion plants operated with solid fuels can be influenced both by suitable control of the combustion process, so-called primary measures, and by treatment of the flue gases withdrawn from the furnace, so-called secondary measures.

Während die Primärmaßnahmen die Entstehung von Stickoxiden in der Feuerung reduzieren sollen, zielen die Sekundärmaßnahmen darauf ab, entstandene Stickoxide aus den aus der Feuerung abziehenden Rauchgasen wieder zu entfernen.While the primary measures are to reduce the formation of nitrogen oxides in the furnace, the secondary measures aim to remove nitrogen oxides from the flue gases that are extracted from the furnace.

Bekannte Sekundärmaßnahmen sind beispielsweise die katalytischen Verfahren zur selektiven Abtrennung der Stickoxide. Diese Verfahren sind jedoch aufwendig und teuer. Auch ist die Entsorgung der aufgebrauchten bzw. beladenen katalysatoren nicht unproblematisch.Known secondary measures are, for example, the catalytic processes for the selective separation of the nitrogen oxides. However, these processes are complex and expensive. The disposal of used or loaded catalysts is also not without problems.

Eine weitere, vergleichsweise einfache Möglichkeit zur Verringerung der Stickoxidemission besteht darin, den aus der Hauptfeuerungszone einer Feuerungsanlage abziehenden Rauchgasen zusätzlichen Reduktionsbrennstoff zuzumischen und in einer sog. Reduktionszone zu verbrennen. Diese Maßnahme reicht jedoch allein meist nicht aus, um die gesetzlich vorgegebenen Emissionsgrenzwerte für Stickoxide einhalten zu können, so daß in der Regel auf zusätzliche Sekundärmaßnahmen, wie z.B. eine katalytische Entstickung nicht verzichtet werden kann.Another, comparatively simple way of reducing the nitrogen oxide emission is to add additional reduction fuel to the flue gases withdrawing from the main combustion zone of a furnace and to burn them in a so-called reduction zone. However, this measure alone is usually not sufficient to be able to comply with the legally prescribed emission limit values for nitrogen oxides, so that usually additional secondary measures, such as e.g. catalytic denitrification cannot be dispensed with.

Aufgabe der Erfindung ist es daher, dieses Verfahren der eingangs beschriebenen Art zu verbessern, so daß auf einfache und wirtschaftliche Weise hohe Entstickungsgrade erreicht werden.The object of the invention is therefore to improve this method of the type described above, so that high degrees of denitrification can be achieved in a simple and economical manner.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß die Rauchgase nacheinander zwei Reduktionszonen durchströmen, daß die erste Reduktionszone unterstöchiometrisch bei Temperaturen oberhalb 1.000° C und unter Zugabe eines Reduktionsbrennstoffes betrieben wird und daß die zweite Reduktionszone überstöchiometrisch in Anwesenheit Stickoxid-reduzierender Stoffe bei Temperaturen von 950°C bis 1.000°C betrieben wird. Als Stickoxid-reduzierende Stoffe werden vornehmlich Ammoniak, Ammoniakwasser, Harnstofflösungen o.ä. eingesetzt.This object is achieved in that the flue gases flow through two reduction zones in succession, that the first reduction zone is operated sub-stoichiometrically at temperatures above 1,000 ° C and with the addition of a reduction fuel and that the second reduction zone is over-stoichiometric in the presence of nitrogen oxide-reducing substances at temperatures of 950 ° C is operated up to 1,000 ° C. Ammonia, ammonia water, urea solutions or the like are mainly used as nitrogen oxide reducing substances. used.

Durch die erfindungsgemäße Kombination der Stickoxidreduktion durch Reduktionsbrennstoff in einer unterstöchiometrischen Reduktionszone und durch Stickoxid-reduzierende Stoffe in einer überstöchiometrischen Reduktionszone wird der Entstickungsgrad insgesamt merklich verbessert.The combination of nitrogen oxide reduction by reducing fuel in a substoichiometric reduction zone and by nitrogen oxide reducing substances in a superstoichiometric reduction zone according to the invention significantly improves the degree of denitrification.

Zweckmäßigerweise werden die Stickstoff-reduzierenden Stoffe, zumindest teilweise, zusammen mit dem Reduktionsbrennstoff in die erste Reduktionszone zugegeben. Dadurch wird bereits in der ersten Reduktionszone die Stickoxidreduktion weiter deutlich gesteigert, da in der dort vorhandenen unterstöchiometrischen Atmosphäre auch bei den hohen Temperaturen oberhalb 1.000° C die Stickoxid-reduzierenden Stoffe zusätzlich reduzierend wirken. Die Verweilzeit der Rauchgase in dieser ersten Reduktionszone sollte zweckmäßigerweise mindestens 0,1 s betragen.The nitrogen-reducing substances are expediently added, at least partially, together with the reduction fuel to the first reduction zone. As a result, the nitrogen oxide reduction is further increased significantly in the first reduction zone, since in the substoichiometric atmosphere there the nitrogen oxide reducing substances also have a reducing effect even at high temperatures above 1,000 ° C. The residence time of the flue gases in this first reduction zone should expediently be at least 0.1 s.

In der zweiten Reduktionszone findet dann durch die Stickoxid-reduzierenden Stoffe die weitere Stickoxidminderung statt, wobei jedoch wegen der überstöchiometrischen Bedingungen ein Temperaturbereich von 950° C bis 1.000° C eingehalten werden muß. Die Einstellung der überstöchiometrischen Bedingungen in der zweiten Reduktionsstufe erfolgt zweckmäßigerweise durch Zugabe einer Überschußmenge an Ausbrandluft über den zum vollständigen Ausbrennen der Reduktionsmenge benötigten Bedarf hinaus.In the second reduction zone, the nitrogen oxide-reducing substances then further reduce the nitrogen oxide, although a temperature range of 950 ° C. to 1,000 ° C. must be maintained due to the stoichiometric conditions. The setting of the superstoichiometric conditions in the second reduction stage is expediently carried out by adding an excess amount of burnout air beyond what is required to completely burn out the reduction amount.

Gemäß einem weiteren Merkmal der Erfindung kann über die Menge und Temperatur der zugeführten Ausbrandluft der bei überstöchiometrischen Bedingungen einzuhaltende enge Temperaturbereich einfach und genau eingehalten werden. Da die Stickoxid-reduzierenden Stoffe bereits in der ersten Reduktionszone zugemischt werden, ist sichergestellt, daß sie gleichmäßig im Rauchgas verteilt den für die Stickoxidminderung einzuhaltenden Temperaturbereich durchlaufen.According to a further feature of the invention, the narrow temperature range to be maintained under superstoichiometric conditions can be maintained simply and precisely via the amount and temperature of the combustion air supplied. Since the nitrogen oxide-reducing substances are already mixed in the first reduction zone, it is ensured that they are distributed evenly in the flue gas through the temperature range to be observed for the nitrogen oxide reduction.

Das erfindungsgemäße Verfahren wird anhand einer in der Figur beispielhaft dargestellten Schmelzkammerfeuerung weiter erläutert.The method according to the invention is further explained on the basis of a melting chamber firing shown by way of example in the figure.

Eine Feuerungsanlage 1 weist eine Hauptfeuerungszone 2 mit Brennern 10 und einer Brennstoffzuführung 7 auf. Die Rauchgase der Hauptfeuerungszone 2 werden im gezeigten Beispiel einer Schmelzkammerfeuerung um 180° umgelenkt und durch einen Fangrost 4 geleitet. Der umgelenkte Rauchgasstrom durchströmt dann nacheinander zwei Reduktionszonen 6 und 9. In die erste Reduktionszone 6 mit unterstöchiometrischen Bedingungen und einer Temperatur oberhalb 1.000° C werden über Leitung 5 Reduktionsbrennstoff und über Leitung 3 diesem zudosierte Stickoxid-reduzierende Stoffe in den Rauchgasstrom eingeleitet und mit diesem vermischt. Die Einleitung kann auch, wie in der Figur angedeutet, an mehreren am Umfang der Reduktionszone 6 verteilt angeordneten Einleitstellen erfolgen. Zur Unterstützung der Vermischung durch Erhöhung des Strömungsimpulses kann zusätzlich über Leitung 11 Rauchgas rezirkuliert werden.A firing system 1 has a main firing zone 2 with burners 10 and a fuel feed 7. The flue gases of the main firing zone 2 are deflected by 180 ° in the example of a smelting chamber firing and passed through a grate 4. The redirected flue gas stream then flows through two reduction zones 6 and 9 in succession. In the first reduction zone 6 with substoichiometric conditions and a temperature above 1,000 ° C., reduction fuel is fed in via line 5 and nitrogen oxide-reducing substances metered in via line 3 into the flue gas stream and mixed with it . As indicated in the figure, the introduction can also take place at a plurality of inlet points distributed around the circumference of the reduction zone 6. To support the mixing by increasing the flow pulse, flue gas can additionally be recirculated via line 11.

Die Strömungslänge der ersten Reduktionszone 6 ist ausreichend groß, um eine Verweilzeit der Rauchgase in dieser Reduktionszone 6 von mindestens 0,1 s zu gewährleisten. Über Leitung 7 am Ende der ersten Reduktionszone 6 wird dem Rauchgas eine ausreichend große Menge Ausbrandluft zugemischt, die sicherstellt, daß in der zweiten Reduktionszone 9 überstöchiometrische Bedingungen gegeben sind, wobei über Menge und Temperatur der zugegebenen Ausbrandluft auch der für die Stickoxidminderung in überstöchiometrischer Atmosphäre erforderliche Temperaturbereich von 950° C bis 1.000° C eingestellt wird. Über Leitung 8 können zusätzliche Stickoxid-reduzierende Stoffe, wegen der besseren Vermischung zweckmäßigerweise zusammen mit der Ausbrandluft und ggf. auch hier über Leitung 12 rückgeführtem Rauchgas zudosiert werden, wobei das Verhältnis rezirkuliertes Rauchgas zu Frischluft durch die Bedingungen nach einer überstöchiometrischen Atmosphäre begrenzt ist. Auch hier kann die Einleitung an mehreren, am Umfang der zweiten Reduktionszone 9 verteilt angeordneten Einleitstellen erfolgen.The flow length of the first reduction zone 6 is sufficiently large to ensure that the flue gases remain in this reduction zone 6 for at least 0.1 s. A sufficiently large amount of burnout air is added to the flue gas via line 7 at the end of the first reduction zone 6, which ensures that overstoichiometric conditions are present in the second reduction zone 9, with the amount and temperature of the added burnout air also required for the nitrogen oxide reduction in the overstoichiometric atmosphere Temperature range from 950 ° C to 1,000 ° C is set. Additional nitrogen oxide-reducing substances can be metered in via line 8, because of the better mixing, expediently together with the burnout air and possibly also here returned flue gas via line 12, the ratio of recirculated flue gas to fresh air being limited by the conditions after an over-stoichiometric atmosphere. Here too, the introduction can take place at a plurality of inlet points arranged distributed around the circumference of the second reduction zone 9.

Claims (5)

  1. A process for reducing the emission of nitrogen oxides in the combustion of solid fuels, in particular coal, wherein a reduction fuel is added to the flue gases issuing from a main combustion zone and is post-combusted, characterised in that the flue gases flow successively through two reduction zones, that the first reduction zone is operated sub-stoichiometrically at temperatures exceeding 1,000°C and with the addition of the reduction fuel, and that the second reduction zone is operated super-stoichiometrically in the presence of nitrogen oxide reducing substances at temperatures of 950°C to 1000°C.
  2. A process as claimed in Claim 1, characterised in that the nitrogen oxide reducing substances are added at least partially together with the reduction fuel to the first reduction zone.
  3. A process as claimed in Claim 1 or 2, characterised in that the dwell time of the fuel gases in the first reduction zone amounts to at least 0.1 s.
  4. A process as claimed in one of Claims 1 to 3, characterised in that the setting of the super-stoichiometric conditions in the second reduction zone is carried out by the admixing of combustion air to the flue gases.
  5. A process as claimed in Claim 4, characterised in that the setting of the temperature range in the second reduction zone is carried out via the quantity and temperature of the admixed combustion air.
EP91901273A 1989-12-27 1990-12-21 Process for reducing nox emission during the combustion of solid fuels Expired - Lifetime EP0460160B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT91901273T ATE88257T1 (en) 1989-12-27 1990-12-21 METHOD OF REDUCING NITROUS OXIDE EMISSIONS WHEN FIRING SOLID FUEL.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3943084A DE3943084A1 (en) 1989-12-27 1989-12-27 METHOD FOR REDUCING NITROGEN OXIDE EMISSION IN THE FIRING OF SOLID FUELS
DE3943084 1989-12-27

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EP0460160A1 EP0460160A1 (en) 1991-12-11
EP0460160B1 true EP0460160B1 (en) 1993-04-14

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US (1) US5131335A (en)
EP (1) EP0460160B1 (en)
JP (1) JPH04504899A (en)
AT (1) ATE88257T1 (en)
AU (1) AU631292B2 (en)
DE (2) DE3943084A1 (en)
ES (1) ES2041204T3 (en)
WO (1) WO1991010097A1 (en)

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Publication number Priority date Publication date Assignee Title
US5203267A (en) * 1991-01-22 1993-04-20 New Clear Energy, Inc. Method and apparatus for disposing of waste material
IT1247541B (en) * 1991-05-07 1994-12-17 Ente Naz Energia Elettrica PROCESS FOR REDUCING NITROGEN OXIDES IN COMBUSTION GASES
SE9402789L (en) * 1994-08-19 1995-10-02 Kvaerner Enviropower Ab Method for two-stage combustion of solid fuels in a circulating fluidized bed
US5759022A (en) * 1995-10-16 1998-06-02 Gas Research Institute Method and system for reducing NOx and fuel emissions in a furnace
US5707596A (en) * 1995-11-08 1998-01-13 Process Combustion Corporation Method to minimize chemically bound nox in a combustion process
US5908003A (en) * 1996-08-15 1999-06-01 Gas Research Institute Nitrogen oxide reduction by gaseous fuel injection in low temperature, overall fuel-lean flue gas
DE19938269A1 (en) * 1999-08-12 2001-02-15 Asea Brown Boveri Process for the thermal treatment of solids
US6357367B1 (en) * 2000-07-18 2002-03-19 Energy Systems Associates Method for NOx reduction by upper furnace injection of biofuel water slurry
JP3781706B2 (en) * 2001-10-05 2006-05-31 川崎重工業株式会社 Operation method of ash melting type U firing combustion boiler
FR2941869B1 (en) * 2009-02-10 2013-03-29 Novergie PROCESS FOR REDUCING NITROGEN OXIDES FROM COMBUSTION OF SOLID FUELS
GB2511115A (en) * 2013-02-25 2014-08-27 Linde Ag An end port regenerative furnace

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JPS58120004A (en) * 1982-01-11 1983-07-16 Mitsui Eng & Shipbuild Co Ltd Two-staged combustion
JPS58156104A (en) * 1982-03-10 1983-09-17 Hitachi Zosen Corp Desulfurizing method for inside of furnace in solid combustion furnace
JPS58190605A (en) * 1982-04-28 1983-11-07 Hitachi Zosen Corp Three-stage combustion in restricting nox for performing desulfurization simultaneously
DE3410945A1 (en) * 1984-03-24 1985-10-03 Steag Ag, 4300 Essen METHOD FOR REDUCING NO (ARROW DOWN) X (ARROW DOWN) FORMATION IN COMBUSTION PLANTS, IN PARTICULAR MELT CHAMBER FIREPLACES, AND COMBUSTION SYSTEM FOR IMPLEMENTING THE PROCESS
GB8516826D0 (en) * 1985-07-03 1985-08-07 Dow Chemical Nederland Precursor compositions of nitrogen-containing polyols
DE3614497A1 (en) * 1986-04-29 1987-11-05 Saarbergwerke Ag METHOD AND SYSTEM FOR REDUCING NITROGEN EMISSION IN COMBUSTION OF SOLID FUELS
US4779545A (en) * 1988-02-24 1988-10-25 Consolidated Natural Gas Service Company Apparatus and method of reducing nitrogen oxide emissions
US5078064B1 (en) * 1990-12-07 1999-05-18 Gas Res Inst Apparatus and method of lowering no emissions using diffusion processes

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ES2041204T3 (en) 1993-11-01
AU7038291A (en) 1991-07-24
JPH04504899A (en) 1992-08-27
EP0460160A1 (en) 1991-12-11
US5131335A (en) 1992-07-21
DE3943084A1 (en) 1991-07-04
DE59001211D1 (en) 1993-05-19
WO1991010097A1 (en) 1991-07-11
ATE88257T1 (en) 1993-04-15
AU631292B2 (en) 1992-11-19

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