EP1943461A1 - Process and apparatus for low-nox combustion - Google Patents

Process and apparatus for low-nox combustion

Info

Publication number
EP1943461A1
EP1943461A1 EP05797772A EP05797772A EP1943461A1 EP 1943461 A1 EP1943461 A1 EP 1943461A1 EP 05797772 A EP05797772 A EP 05797772A EP 05797772 A EP05797772 A EP 05797772A EP 1943461 A1 EP1943461 A1 EP 1943461A1
Authority
EP
European Patent Office
Prior art keywords
burner
furnace
oxidizing agent
fuel
gases
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Withdrawn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
EP05797772A
Other languages
German (de)
French (fr)
Inventor
Horst KÖDER
Lothar Backes
Martin Adendorff
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.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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 Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Publication of EP1943461A1 publication Critical patent/EP1943461A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/235—Heating the glass
    • 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 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/006—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber the recirculation taking place in the combustion chamber
    • 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
    • F23C7/06—Disposition of air supply not passing through burner for heating the incoming air
    • 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 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/06—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for completing combustion
    • 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 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/08—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for reducing temperature in combustion chamber, e.g. for protecting walls of combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J11/00—Devices for conducting smoke or fumes, e.g. flues 
    • 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
    • F23L15/00—Heating of air supplied for combustion
    • F23L15/04—Arrangements of recuperators
    • 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
    • F23L7/005—Evaporated water; Steam
    • 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
    • F23L7/007—Supplying oxygen or oxygen-enriched air
    • 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 
    • F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
    • F23C2900/09002—Specific devices inducing or forcing flue gas recirculation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
    • F23D2900/00004—Burners specially adapted for generating high luminous flames, e.g. yellow for fuel-rich mixtures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

Definitions

  • the invention relates to a process and an apparatus for low-NO x combustion using fuel and oxidizing agent and/or furnace off-gases and/or carbon dioxide and/or steam.
  • the furnace off-gases, which are sucked in by a blower, sheath the burner flame, thereby reducing the flame temperature and consequently the thermal emission of NO x .
  • a mixture of oxidizing agent and/or furnace off-gas and/or carbon dioxide and/or steam is burnt with the fuel, which is fed to the burner separately, by means of the burner, which is arranged in a burner block in a refractory lining of a furnace installation.
  • the oxidizing agent is fed to an injector at a pressure of from 0.2 to 40 bar and advantageously having been heated from 20 to 900 0 C in a heat exchanger by means of furnace off-gas.
  • the oxidizing agent may also be fed to the injector directly without being heated.
  • the oxidizing agent which expands as it flows out of the nozzle (which is axially displaceable in the injector at the flow end side), generates a gas jet at a velocity of from 20 to 660 m/s, and thereby generates a reduced pressure in the injector, the sucking action of which sucks either furnace off-gas and/or carbon dioxide (CO 2 ) and/or superheated steam generated from water through heat exchange with furnace off-gas into the jet of oxidizing agent, and this mixture is then fed to the burner, with temperature balancing, in a line connecting the injector to the burner.
  • CO 2 furnace off-gas and/or carbon dioxide
  • a conventional blowing nozzle or some other equivalent technical means can also be used instead of the injector, which is advantageously arranged in a stack provided for discharging the furnace off-gases from the combustion chamber of the furnace installation.
  • the oxidizing agent As an alternative to the oxidizing agent, it is possible for fuel gas at a pressure of from 0.2 to 40 bar to be fed to the injector, hi this case, the oxidizing agent is added to the burner.
  • the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO 2 ) and/or steam which is fed to the burner at a temperature of from 20°C to 1600 0 C, preferably 900 0 C, and at a velocity of from 5 to 70 m/s, has an oxygen content of at least 5% by volume.
  • the burner which is, for example, arranged set back in the burner block, is advantageously a parallel-flow burner with two tubes (inner tube and outer tube) arranged substantially coaxially with respect to one another for feeding fuel and oxi- dizing agent and/or furnace off-gases and/or carbon dioxide and/or steam to the burner mouth.
  • the fuel or the oxidizing-agent mixture may be passed to the burner mouth through the inner tube or through the outer tube.
  • the oxidizing agent used is an oxygen-containing medium with an oxygen content of at least 10% by volume.
  • the fuel used may be any conventional gaseous or liquid fuel, particularly advantageously natural gas.
  • the injector which is advantageously operated with the oxidizing agent, is equipped with an axially displaceable nozzle for controlling the intake quantity and concentration and temperature of the mixture fed to the burner. This eliminates the need to supply the injector with external energy, which entails additional costs.
  • the heat exchanger which is used to heat the oxygen, carbon dioxide and the water and is advantageously arranged in the stack that discharges the furnace off-gases from the combustion chamber of the furnace installation is advantageously a conventional recuperator or regenerator.
  • the burner used is preferably a conventional parallel-flow burner with at least one feed for the oxidizing agent and at least one feed for the fuel, preferably comprising two cylindrical, concentrically arranged tubes.
  • the burner design according to the invention allows the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO 2 ) and/or steam to flow out of the burner mouth of the burner at a velocity which is 0.3 to 4 times higher than the fuel, with the result that a total momentum flux, based on the burner power, of from 1.5 to 8 NMW and a ratio of the momentum flux densities of the mixture of oxidizing agent and furnace off-gases to fuel of from 0.8 to 31 are ensured, and as a result a power density of from 0.2 to 0.5 KW/mm 2 is reached at the outlet of the burner block.
  • the outlet velocity of the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO 2 ) and/or steam is between 20 and 80 m/s at the burner mouth.
  • the burner may also be arranged on the off-gas side of the furnace installation, preferably in the stack which discharges the furnace off-gases from the combustion chamber of the furnace installation, or at any other location which is suitable for its intended use in the furnace wall surrounding the combustion chamber of the furnace installation.
  • the injector and the heat exchanger are arranged in the burner.
  • An injector/heat exchanger arrangement of this type is advantageous if the furnace off-gas is extracted through an annular gap around the burner mouth, as for example in the case of rotary drum furnaces, in particular when the burner is in- stalled on the off-gas side of the furnace.
  • the mixture of oxfdizing agent and/or furnace off-gas and/or carbon dioxide and/or steam is recuperatively heated by the furnace off-gases.
  • the lines which carry the oxidizing agent, the furnace off-gas, the carbon dioxide and the steam consist of heat-resistant and corrosion-resistant NiCr or ODS alloys and are provided with an insulation which ensures the required thermal protection from the inside and/or the outside and preferably ceramic fibres.
  • the burner block which includes the burner preferably has a cylindrical opening.
  • the burner is equipped with a UV light receiver for flame monitoring.
  • the mixture of oxidizing agent and/or furnace off-gas and/or carbon dioxide and/or steam which is fed to the burner in accordance with the invention reduces the reaction rate of the combustion, since the reactions of the oxygen with the fuel are impeded by the CO 2 and/or H 2 O molecules.
  • the mixing of the oxidizing agent with furnace gas and/or carbon dioxide and/or steam results in the formation of a voluminous combustion flame with a high concentration of carbon dioxide and steam.
  • the greater volume of the flame compared to that achieved with known combustion, and the higher concentration of carbon dioxide and/or steam in the burner flame significantly increase the gas radiation of carbon dioxide and/or steam, which takes place in the spectral region in radiation bands, with the result that the material to be treated can be heated by a flame temperature which lowers the levels of NO x in the off-gas.
  • the radiation bands which are relevant to carbon dioxide are in the range from 2.4 to 3 ⁇ m, 4 to 4.8 ⁇ m, 12.5 to 16.4 ⁇ m, and those which are relevant to steam are in the range from 1.7 to 2 ⁇ m, 2.2 to 3 ⁇ m and 12 to 30 ⁇ m.
  • this mixture is mixed in such a manner with the fuel at the burner mouth that the combustion takes place at a flame temperature of from 800°C to 2700°C, which significantly reduces the thermal NO x off-gas potential of the furnace installation.
  • the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide and/or steam which is fed to the burner, as well as the burner which is used in accordance with the invention, causes the fuel to be at least partially self-carburized in the fuel tube of the burner and, owing to the design of the burner, in the fuel-rich core of the burner flame.
  • the self-carburization or decomposition takes place in oxygen-free zones and at temperatures of greater than 1000°C in the case of hy- drocarbons, so as to form soot.
  • the heating of the soot particles in the burner flame leads to continuous radiation in the range from 0.2 to 20 micrometers and therefore to cooling of the flame, so that the NO x off-gas levels from the furnace installation are additionally lowered.
  • a further advantage is the improved heating of lower layers, e.g. in a glass melt bath, since liquid glass is semi-transparent to wavelengths in the range from 0.3 to 4 micrometers.
  • the NO x off-gas levels are additionally reduced by the use of preferably low-TM 2 oxidizing agent mixtures and fuels.
  • the circulating furnace gases cause nitrogen oxides which are present in the com- bustion chamber of the furnace installation to be fed to the burner flame, and these nitrogen oxides are then reduced to form nitrogen (N 2 ) in the fuel-rich zones of the burner flame.
  • the very long, soft and visible flames generated in the combustion chamber of the furnace installation allow particularly advantageous low-NO x combustion in aluminium holding furnaces and rotary drum furnaces.
  • the combustion according to the invention is stable and low-noise.
  • the noise level is 50-80 Decibels.
  • the flame radiation in the visible region advantageously increases the heat transfer to the material to be treated.
  • the high concentration and volume of CO 2 /H 2 O vapour in the burner flame additionally increases the gas radiation of CO 2 and/or H 2 O vapour, which takes place in the spectral region in radiation bands, in such a manner as to ensure improved heat transfer to the material to be treated, e.g. when melting glass.
  • the injector insert significantly reduces the wear and maintenance costs for the furnace installation incurred, for example, with a blower consisting of expensive heat-resistant materials which has hitherto been used. Moreover, the supply of external energy which has hitherto been required to operate the blower is no longer necessary. Furthermore, the thermal loading and therefore wear to the pipe tubes is reduced, since the mixing of the oxidizing agent with furnace off-gases and/or carbon dioxide and/or steam lowers the temperature of the media that are to be transported.
  • the Io W-NO x combustion according to the invention with a uniform temperature distribution at a low temperature level (burner flame) in the combustion chamber and therefore with a significantly reduced NO x off-gas potential can be used in any conventional furnace installation, particularly advantageously in aluminium holding furnaces or glass-melting furnaces.
  • Fig. 1 diagrammatically depicts a furnace installation with combustion apparatus
  • Fig. 2 diagrammatically depicts a further furnace installation with combustion apparatus
  • Fig. 3 diagrammatically depicts a third furnace installation with combustion appa- ratus.
  • the furnace installation illustrated in Fig. 1 comprises a refractory lining 1 which surrounds a combustion chamber and has an off-gas opening 19 and a stack 2, which discharges the furnace off-gases, and pipeline 3 as well as a burner block 4 with a burner 5, the burner 5 being connected by a pipeline 7 to an injector 6 and to a heat exchanger 8 arranged in the stack 2.
  • the furnace off-gases which flow out of the combustion chamber through the off- gas opening 19 are cooled as they flow around the heat exchanger 8 and then flow out of the furnace installation through the stack 2.
  • the gaseous oxygen which is used as oxidizing agent at a temperature of from -20 to 4O 0 C and at a pressure of from 0.2 to 40 bar, flows into the heat exchanger 8 through an inlet 9.
  • the oxygen flowing through the heat exchanger 8 which is designed as a recuperator or regenerator, is heated by the furnace off-gases flowing around the heat exchanger 8 and flows through an outlet 10 of the heat exchanger 8 into the injector 6 through an inlet 11 at a temperature of from 20 to 900 0 C.
  • the high flow velocity of the oxygen jet generates a reduced pressure at position 13 in the injector 6, the sucking action of which reduced pressure sucks the furnace off-gases out of the combustion chamber through the pipeline 3 into the oxygen jet, and in the pipeline 7, which is designed as a mixing section of length x, they are mixed with the oxygen jet, with temperature balancing, after which the mixture of oxygen and furnace off-gases is fed, at a temperature of from 20 to 1600 0 C, through a connection 14 to the burner 5, which via a further connection 15 is supplied with natural gas as gaseous fuel.
  • the pipelines carrying the oxygen and the furnace off-gases consist of a heat- resistant NiCr or ODS alloy and are provided on the inner side with a thermal protection and/or on the outer side with a thermal insulation, e.g. comprising ceramic fibres or ceramic blocks.
  • the burner 5, which is used as a parallel-flow burner advantageously has an inner tube and an outer tube, with the natural gas used as gaseous fuel flowing to the burner mouth 16 through the fuel tube 18, which is arranged as the inner tube, and the mixture of oxygen and furnace off-gas flowing to the burner mouth 16 through the outer tube, which accommodates fuel tube 18 and is designed as an annular gap 21, generating a long, soft and visible burner flame 17 in the combustion chamber of the furnace installation for heating material that is to be treated.
  • Partial self-carburization of the fuel takes place in the fuel tube 18 of the burner 5 through recuperative heat exchange with the mixture of oxidizing agent and furnace off-gases.
  • the burner structure according to the invention allows the mixture of oxidizing agent and furnace off-gases to flow out bf the burner mouth 16 of the burner at a velocity which is 0.3 to 4 times higher than the fuel, with the result that a total momentum flux, based on the burner power, of from 1.5 to 8 N/MW and a ratio of the momentum flux densities of the mixture of oxidizing agent and furnace off- gases to fuel of from 0.8 to 31 are ensured, and as a result a power density of from 0.2 to 0.5 KW/mm 2 is reached at the outlet of the burner block 4.
  • the mixture of oxidizing agent and furnace off-gases flows out of the burner mouth 16 at a velocity of from 20 to 80 m/s.
  • the burner flame which burns the material that is to be treated in the combustion chamber has a flame temperature of from 800 °C to 2700 0 C.
  • the burner block 4 which accommodates the burner 5 has a preferably cylindrical opening.
  • the burner is advantageously equipped with a UV light receiver 20 for flame monitoring.
  • the furnace installation which is diagrammatically depicted in Fig. 2 is advantageously used if the furnace off-gases are ladened with dust or other substances which are aggressive or promote oxidation.
  • This furnace installation comprises the refractory lining 1, which surrounds a combustion chamber of a furnace installa- tion and has an off-gas opening 19, and a stack 2, which discharges the furnace off-gas and accommodates the heat exchanger 8, as well as the burner block 4, which contains the burner 5 and is connected by a pipeline 7 to the injector 6 and the heat exchanger 8.
  • the furnace off-gases which flow out of the combustion chamber through the off- gas opening 19 are cooled as they flow around the heat exchanger 8, which is supplied with water, and then flow out of the furnace installation via the stack 2.
  • the water which is fed to the heat exchanger 8 through the inlet 9 is evaporated through heat exchange with the furnace off-gas flowing around the heat exchanger 8 and then flows into the injector 6 at position 13 as superheated steam at a temperature of from 20 to 900°C.
  • the gaseous oxygen which is used as oxidizing agent at a temperature of from -20 to 40°C and a pressure of from 0.2 to 40 bar, flows into the injector 6 through the inlet 11.
  • the oxygen jet expanding as it flows out of the outflow nozzle 12 of the injector 6 increases its flow velocity to 20 to 340 m/s, with the result that a reduced pressure is generated at position 13 in the injector 6, the sucking action of which reduced pressure sucks the superheated steam into the oxygen jet flowing through the injector 6 at position 13 and mixes it with the oxygen jet, with temperature balancing, in the pipeline 7, which is designed as mixing section of length x, and the oxygen/steam mixture flows, at a temperature of from 20 to 1600°C, through connection 14 into the burner 5, which is supplied through connection 15 with natural gas as gaseous fuel.
  • the pipelines carrying the oxygen and the steam consist of a heat-resistant and corrosion-resistant NiCr or ODS alloy and are designed from the inside with a thermal protection or from the outside with a thermal insulation, e.g. comprising a ceramic fibre or ceramic block.
  • the burner 5, which is used as a parallel-flow burner advantageously has an inner tube and an outer tube, natural gas which is used as gaseous fuel flowing to the burner mouth 16 through the fuel tube 18, which is arranged as an inner tube, and the mixture of oxygen and steam flowing to the burner mouth 16 through the outer tube, which accommodates the fuel tube 18 and is designed as an annular gap 21, thereby generating the long, soft and visible burner flame 17 with a flame tempera- tare of from 800°C to 2700°C in the combustion chamber of the furnace installation for heating material that is to be treated.
  • Partial self-carburization of the fuel takes place in the fuel tube 18 of the burner 5 through recuperative heat exchange with the mixture of oxidizing agent and steam.
  • the burner design according to the invention allows the mixture of oxidizing agent and steam to flow out of the burner mouth 16 of the burner at a velocity which is 0.3 to 4 times higher than the fuel, with the result that a total momentum flux, based on the burner power, of from 1.5 to 8 N/MW and a ratio of the momentum flux densities of the mixture of oxidizing agent and steam to fuel of from 0.8 to 31 are ensured, and as a result a power density of from 0.2 to 0.5 KW/mm is reached at the outlet of the burner block 4.
  • the mixture of oxidizing agent and steam flows out of the burner mouth 16 at a velocity of from 20 to 80 m/s.
  • the burner block 4 has a preferably cylindrical opening.
  • the burner is equipped with a UV light receiver 20 for flame monitoring.
  • the furnace installation which is diagrammatically depicted in Fig. 3 is used if the furnace off-gases are ladened with dust or other aggressive or oxidation-promoting substances.
  • This furnace installation comprises the refractory lining 1, which surrounds a combustion chamber and has an off-gas opening 19, and the stack 2, which is designed to discharge the furnace off-gas and contains the heat exchanger 8, as well as the burner block 4 with burner 5, burner 5 being connected to the injector 6 and to the heat exchanger 8 by a pipeline 7.
  • the exhaust gases which flow out of the combustion chamber through the off-gas opening 19 are cooled as they flow around the heat exchanger 8, which is supplied with carbon dioxide, and then flow out of the furnace installation through the stack 2.
  • Liquid or preferably gaseous carbon dioxide which is supplied through the inlet 9 of the heat exchanger 8 is heated to 20°C to 900°C through heat exchange with the furnace off-gas flowing around the heat exchanger 8 and flows through the outlet 10 into the injector 6 at position 13.
  • the gaseous oxygen which is used as oxidizing agent at a temperature of from -20 to 4O 0 C and a pressure of from 0.2 to 40 bar, is fed to the injector 6 through the inlet 11.
  • the oxygen flowing through the injector 6 expands as it flows out of the outflow nozzle 12 of the injector, so that its flow velocity is increased to from 20 to 340 m/s, with the result that a reduced pressure is generated in the injector 6 at position 13, the sucking action of which reduced pressure sucks the carbon dioxide into the oxygen jet, with the carbon dioxide being mixed with the oxygen jet, with temperature balancing, in the pipeline 7, which is designed as a mixing section with a length x, and then the mixture of oxygen and carbon dioxide flows, at a temperature of from 20 to 1600 0 C, through connection 14 into the burner 5, which is supplied via a further connection 15 with natural gas as gaseous fuel.
  • the pipelines carrying the oxygen and the carbon dioxide consist of a heat- resistant and corrosion-resistant NiCr or ODS alloy and are provided on the inner side with a thermal protection and/or on the outer side with a thermal insulation, e.g. comprising ceramic fibres.
  • the burner 5, which is used as a parallel-flow burner advantageously has an inner tube and an outer tube, with natural gas used as gaseous fuel being fed to the burner mouth 16 through the fuel tube 18, which is arranged as the inner tube, and the mixture of oxygen and carbon dioxide being fed to the burner mouth 16 through the outer tube, which accommodates the fuel tube 18 and is designed as an annular gap 21, producing a long, soft and visible burner flame 17 with a flame temperature of from 800-2700°C in the combustion chamber of the furnace installation for heating material that is to be treated.
  • Partial self-carburization of the fuel takes place in the fuel tube 18 of the burner 5 through recuperative heat exchange with the mixture of oxidizing agent and carbon dioxide.
  • the burner design according to the invention allows the mixture of oxidizing agent and carbon dioxide to flow out of the burner mouth 16 of the burner at a velocity which is 0.3 to 4 times higher than the fuel, with the result that a total momentum flux, based on the burner power, of from 1.5 to 8 N/MW and a ratio of the momentum flux densities of the mixture of oxidizing agent and carbon dioxide to fuel of from 0.8 to 31 are ensured, and as a result a power density of from 0.2 to 0.5 KW/mm 2 is reached at the outlet of the burner block 4.
  • the mixture of oxidizing agent and carbon dioxide flows out of the burner mouth 16 at a velocity of from 20 to 80 m/s.
  • the burner block 4 has a preferably cylindrical opening.
  • the burner is equipped with a UV light receiver 20 for flame monitoring.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Air Supply (AREA)
  • Combustion Of Fluid Fuel (AREA)

Abstract

The invention relates to a process and an apparatus for low-NOx combustion with at least one burner (5) using fuel and oxidizing agent and/or furnace off-gases and/or carbon dioxide and/or steam. The low-NOx combustion according to the invention can be used in conventional melting and holding furnaces, in particular in aluminium holding furnaces or rotary drum furnaces and glass-melting furnaces, with the potential for considerable economies to be made.

Description

Process and apparatus for low-NOx combustion
The invention relates to a process and an apparatus for low-NOx combustion using fuel and oxidizing agent and/or furnace off-gases and/or carbon dioxide and/or steam.
In the known low-NOx combustion, the furnace off-gases, which are sucked in by a blower, sheath the burner flame, thereby reducing the flame temperature and consequently the thermal emission of NOx.
However, this conventional combustion has the significant drawback that the furnace off-gases which are recirculated in the furnace installation are not completely mixed with the oxidizing agent, and consequently the stipulated emission of NOx in the off-gas can only be realized at additional cost.
High investment costs are inevitable with the known low-NOx combustion, and costs are additionally incurred for maintenance of the installation, in particular the highly loaded blower and the pipelines. Moreover, external energy is required to operate the blower.
Therefore, it is an object of the present invention to provide a process and an apparatus which allow economical and low-pollutant (low-NOx) combustion in conven- tional furnace installations.
This object is achieved by a process having the features of Claim 1 and by an apparatus having the features of Claim 13.
Advantageous refinements of the invention are given in the subclaims.
According to the invention, a mixture of oxidizing agent and/or furnace off-gas and/or carbon dioxide and/or steam is burnt with the fuel, which is fed to the burner separately, by means of the burner, which is arranged in a burner block in a refractory lining of a furnace installation.
For this purpose, the oxidizing agent is fed to an injector at a pressure of from 0.2 to 40 bar and advantageously having been heated from 20 to 9000C in a heat exchanger by means of furnace off-gas. The oxidizing agent may also be fed to the injector directly without being heated.
The oxidizing agent, which expands as it flows out of the nozzle (which is axially displaceable in the injector at the flow end side), generates a gas jet at a velocity of from 20 to 660 m/s, and thereby generates a reduced pressure in the injector, the sucking action of which sucks either furnace off-gas and/or carbon dioxide (CO2) and/or superheated steam generated from water through heat exchange with furnace off-gas into the jet of oxidizing agent, and this mixture is then fed to the burner, with temperature balancing, in a line connecting the injector to the burner.
A conventional blowing nozzle or some other equivalent technical means can also be used instead of the injector, which is advantageously arranged in a stack provided for discharging the furnace off-gases from the combustion chamber of the furnace installation.
As an alternative to the oxidizing agent, it is possible for fuel gas at a pressure of from 0.2 to 40 bar to be fed to the injector, hi this case, the oxidizing agent is added to the burner.
The mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO2) and/or steam, which is fed to the burner at a temperature of from 20°C to 16000C, preferably 9000C, and at a velocity of from 5 to 70 m/s, has an oxygen content of at least 5% by volume.
The burner, which is, for example, arranged set back in the burner block, is advantageously a parallel-flow burner with two tubes (inner tube and outer tube) arranged substantially coaxially with respect to one another for feeding fuel and oxi- dizing agent and/or furnace off-gases and/or carbon dioxide and/or steam to the burner mouth. The fuel or the oxidizing-agent mixture may be passed to the burner mouth through the inner tube or through the outer tube.
The oxidizing agent used is an oxygen-containing medium with an oxygen content of at least 10% by volume.
The fuel used may be any conventional gaseous or liquid fuel, particularly advantageously natural gas.
The injector, which is advantageously operated with the oxidizing agent, is equipped with an axially displaceable nozzle for controlling the intake quantity and concentration and temperature of the mixture fed to the burner. This eliminates the need to supply the injector with external energy, which entails additional costs.
The heat exchanger which is used to heat the oxygen, carbon dioxide and the water and is advantageously arranged in the stack that discharges the furnace off-gases from the combustion chamber of the furnace installation is advantageously a conventional recuperator or regenerator.
The burner used is preferably a conventional parallel-flow burner with at least one feed for the oxidizing agent and at least one feed for the fuel, preferably comprising two cylindrical, concentrically arranged tubes.
The burner design according to the invention allows the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO2) and/or steam to flow out of the burner mouth of the burner at a velocity which is 0.3 to 4 times higher than the fuel, with the result that a total momentum flux, based on the burner power, of from 1.5 to 8 NMW and a ratio of the momentum flux densities of the mixture of oxidizing agent and furnace off-gases to fuel of from 0.8 to 31 are ensured, and as a result a power density of from 0.2 to 0.5 KW/mm2 is reached at the outlet of the burner block. The outlet velocity of the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO2) and/or steam is between 20 and 80 m/s at the burner mouth.
The burner may also be arranged on the off-gas side of the furnace installation, preferably in the stack which discharges the furnace off-gases from the combustion chamber of the furnace installation, or at any other location which is suitable for its intended use in the furnace wall surrounding the combustion chamber of the furnace installation.
It is also possible for the injector and the heat exchanger to be arranged in the burner. An injector/heat exchanger arrangement of this type is advantageous if the furnace off-gas is extracted through an annular gap around the burner mouth, as for example in the case of rotary drum furnaces, in particular when the burner is in- stalled on the off-gas side of the furnace. In this case, the mixture of oxfdizing agent and/or furnace off-gas and/or carbon dioxide and/or steam is recuperatively heated by the furnace off-gases.
The lines which carry the oxidizing agent, the furnace off-gas, the carbon dioxide and the steam consist of heat-resistant and corrosion-resistant NiCr or ODS alloys and are provided with an insulation which ensures the required thermal protection from the inside and/or the outside and preferably ceramic fibres.
The burner block which includes the burner preferably has a cylindrical opening.
The burner is equipped with a UV light receiver for flame monitoring.
The mixture of oxidizing agent and/or furnace off-gas and/or carbon dioxide and/or steam which is fed to the burner in accordance with the invention reduces the reaction rate of the combustion, since the reactions of the oxygen with the fuel are impeded by the CO2 and/or H2O molecules.
The mixing of the oxidizing agent with furnace gas and/or carbon dioxide and/or steam results in the formation of a voluminous combustion flame with a high concentration of carbon dioxide and steam. The greater volume of the flame compared to that achieved with known combustion, and the higher concentration of carbon dioxide and/or steam in the burner flame significantly increase the gas radiation of carbon dioxide and/or steam, which takes place in the spectral region in radiation bands, with the result that the material to be treated can be heated by a flame temperature which lowers the levels of NOx in the off-gas. The radiation bands which are relevant to carbon dioxide are in the range from 2.4 to 3 μm, 4 to 4.8 μm, 12.5 to 16.4 μm, and those which are relevant to steam are in the range from 1.7 to 2 μm, 2.2 to 3 μm and 12 to 30 μm.
As a result of the high-viscosity mixture of oxidizing agent and/or furnace off- gases and/or carbon dioxide and/or steam being fed to the burner at a temperature of from 20°C to 16000C, preferably 900°C, this mixture is mixed in such a manner with the fuel at the burner mouth that the combustion takes place at a flame temperature of from 800°C to 2700°C, which significantly reduces the thermal NOx off-gas potential of the furnace installation.
The mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide and/or steam which is fed to the burner, as well as the burner which is used in accordance with the invention, causes the fuel to be at least partially self-carburized in the fuel tube of the burner and, owing to the design of the burner, in the fuel-rich core of the burner flame. The self-carburization or decomposition takes place in oxygen-free zones and at temperatures of greater than 1000°C in the case of hy- drocarbons, so as to form soot. The heating of the soot particles in the burner flame leads to continuous radiation in the range from 0.2 to 20 micrometers and therefore to cooling of the flame, so that the NOx off-gas levels from the furnace installation are additionally lowered.
A further advantage is the improved heating of lower layers, e.g. in a glass melt bath, since liquid glass is semi-transparent to wavelengths in the range from 0.3 to 4 micrometers. The NOx off-gas levels are additionally reduced by the use of preferably low-TM2 oxidizing agent mixtures and fuels.
The circulating furnace gases cause nitrogen oxides which are present in the com- bustion chamber of the furnace installation to be fed to the burner flame, and these nitrogen oxides are then reduced to form nitrogen (N2) in the fuel-rich zones of the burner flame.
The very long, soft and visible flames generated in the combustion chamber of the furnace installation allow particularly advantageous low-NOx combustion in aluminium holding furnaces and rotary drum furnaces.
Moreover, the combustion according to the invention is stable and low-noise. The noise level is 50-80 Decibels.
With the low-NOx combustion according to the invention - unlike with the known flame-free combustion - the flame radiation in the visible region advantageously increases the heat transfer to the material to be treated.
The high concentration and volume of CO2/H2O vapour in the burner flame additionally increases the gas radiation of CO2 and/or H2O vapour, which takes place in the spectral region in radiation bands, in such a manner as to ensure improved heat transfer to the material to be treated, e.g. when melting glass.
Furthermore, the turbulence and swirling during combustion, which have a disruptive influence when dust-containing products are introduced, are reduced.
The injector insert significantly reduces the wear and maintenance costs for the furnace installation incurred, for example, with a blower consisting of expensive heat-resistant materials which has hitherto been used. Moreover, the supply of external energy which has hitherto been required to operate the blower is no longer necessary. Furthermore, the thermal loading and therefore wear to the pipe tubes is reduced, since the mixing of the oxidizing agent with furnace off-gases and/or carbon dioxide and/or steam lowers the temperature of the media that are to be transported.
In addition, primary energy can be saved through preheating of the oxygen used as oxidizing agent and/or carbon dioxide and/or steam by furnace off-gases in the heat exchanger, and as a result the operating costs of the furnace installation can be reduced further.
The Io W-NOx combustion according to the invention, with a uniform temperature distribution at a low temperature level (burner flame) in the combustion chamber and therefore with a significantly reduced NOx off-gas potential can be used in any conventional furnace installation, particularly advantageously in aluminium holding furnaces or glass-melting furnaces.
The invention is explained in more detail below on the basis of an exemplary embodiment illustrated in the drawing, in which:
Fig. 1 diagrammatically depicts a furnace installation with combustion apparatus;
Fig. 2 diagrammatically depicts a further furnace installation with combustion apparatus;
Fig. 3 diagrammatically depicts a third furnace installation with combustion appa- ratus.
The furnace installation illustrated in Fig. 1 comprises a refractory lining 1 which surrounds a combustion chamber and has an off-gas opening 19 and a stack 2, which discharges the furnace off-gases, and pipeline 3 as well as a burner block 4 with a burner 5, the burner 5 being connected by a pipeline 7 to an injector 6 and to a heat exchanger 8 arranged in the stack 2.
The furnace off-gases which flow out of the combustion chamber through the off- gas opening 19 are cooled as they flow around the heat exchanger 8 and then flow out of the furnace installation through the stack 2.
The gaseous oxygen, which is used as oxidizing agent at a temperature of from -20 to 4O0C and at a pressure of from 0.2 to 40 bar, flows into the heat exchanger 8 through an inlet 9.
The oxygen flowing through the heat exchanger 8, which is designed as a recuperator or regenerator, is heated by the furnace off-gases flowing around the heat exchanger 8 and flows through an outlet 10 of the heat exchanger 8 into the injector 6 through an inlet 11 at a temperature of from 20 to 9000C.
The oxygen which flows out of the outflow nozzle 12 of the injector 6 at a velocity of from 20 to 660 m/s expands, thereby generating an oxygen jet flowing at a ve- locity of from 20 to 660 m/s.
The high flow velocity of the oxygen jet generates a reduced pressure at position 13 in the injector 6, the sucking action of which reduced pressure sucks the furnace off-gases out of the combustion chamber through the pipeline 3 into the oxygen jet, and in the pipeline 7, which is designed as a mixing section of length x, they are mixed with the oxygen jet, with temperature balancing, after which the mixture of oxygen and furnace off-gases is fed, at a temperature of from 20 to 16000C, through a connection 14 to the burner 5, which via a further connection 15 is supplied with natural gas as gaseous fuel.
The pipelines carrying the oxygen and the furnace off-gases consist of a heat- resistant NiCr or ODS alloy and are provided on the inner side with a thermal protection and/or on the outer side with a thermal insulation, e.g. comprising ceramic fibres or ceramic blocks.
The burner 5, which is used as a parallel-flow burner, advantageously has an inner tube and an outer tube, with the natural gas used as gaseous fuel flowing to the burner mouth 16 through the fuel tube 18, which is arranged as the inner tube, and the mixture of oxygen and furnace off-gas flowing to the burner mouth 16 through the outer tube, which accommodates fuel tube 18 and is designed as an annular gap 21, generating a long, soft and visible burner flame 17 in the combustion chamber of the furnace installation for heating material that is to be treated.
Partial self-carburization of the fuel takes place in the fuel tube 18 of the burner 5 through recuperative heat exchange with the mixture of oxidizing agent and furnace off-gases.
The burner structure according to the invention allows the mixture of oxidizing agent and furnace off-gases to flow out bf the burner mouth 16 of the burner at a velocity which is 0.3 to 4 times higher than the fuel, with the result that a total momentum flux, based on the burner power, of from 1.5 to 8 N/MW and a ratio of the momentum flux densities of the mixture of oxidizing agent and furnace off- gases to fuel of from 0.8 to 31 are ensured, and as a result a power density of from 0.2 to 0.5 KW/mm2 is reached at the outlet of the burner block 4.
The mixture of oxidizing agent and furnace off-gases flows out of the burner mouth 16 at a velocity of from 20 to 80 m/s.
The burner flame which burns the material that is to be treated in the combustion chamber has a flame temperature of from 800 °C to 2700 0C.
The burner block 4 which accommodates the burner 5 has a preferably cylindrical opening.
The burner is advantageously equipped with a UV light receiver 20 for flame monitoring.
The furnace installation which is diagrammatically depicted in Fig. 2 is advantageously used if the furnace off-gases are ladened with dust or other substances which are aggressive or promote oxidation. This furnace installation comprises the refractory lining 1, which surrounds a combustion chamber of a furnace installa- tion and has an off-gas opening 19, and a stack 2, which discharges the furnace off-gas and accommodates the heat exchanger 8, as well as the burner block 4, which contains the burner 5 and is connected by a pipeline 7 to the injector 6 and the heat exchanger 8.
The furnace off-gases which flow out of the combustion chamber through the off- gas opening 19 are cooled as they flow around the heat exchanger 8, which is supplied with water, and then flow out of the furnace installation via the stack 2.
As it flows through the heat exchanger 8, the water which is fed to the heat exchanger 8 through the inlet 9 is evaporated through heat exchange with the furnace off-gas flowing around the heat exchanger 8 and then flows into the injector 6 at position 13 as superheated steam at a temperature of from 20 to 900°C.
The gaseous oxygen, which is used as oxidizing agent at a temperature of from -20 to 40°C and a pressure of from 0.2 to 40 bar, flows into the injector 6 through the inlet 11. The oxygen jet expanding as it flows out of the outflow nozzle 12 of the injector 6 increases its flow velocity to 20 to 340 m/s, with the result that a reduced pressure is generated at position 13 in the injector 6, the sucking action of which reduced pressure sucks the superheated steam into the oxygen jet flowing through the injector 6 at position 13 and mixes it with the oxygen jet, with temperature balancing, in the pipeline 7, which is designed as mixing section of length x, and the oxygen/steam mixture flows, at a temperature of from 20 to 1600°C, through connection 14 into the burner 5, which is supplied through connection 15 with natural gas as gaseous fuel.
The pipelines carrying the oxygen and the steam consist of a heat-resistant and corrosion-resistant NiCr or ODS alloy and are designed from the inside with a thermal protection or from the outside with a thermal insulation, e.g. comprising a ceramic fibre or ceramic block.
The burner 5, which is used as a parallel-flow burner, advantageously has an inner tube and an outer tube, natural gas which is used as gaseous fuel flowing to the burner mouth 16 through the fuel tube 18, which is arranged as an inner tube, and the mixture of oxygen and steam flowing to the burner mouth 16 through the outer tube, which accommodates the fuel tube 18 and is designed as an annular gap 21, thereby generating the long, soft and visible burner flame 17 with a flame tempera- tare of from 800°C to 2700°C in the combustion chamber of the furnace installation for heating material that is to be treated.
Partial self-carburization of the fuel takes place in the fuel tube 18 of the burner 5 through recuperative heat exchange with the mixture of oxidizing agent and steam.
The burner design according to the invention allows the mixture of oxidizing agent and steam to flow out of the burner mouth 16 of the burner at a velocity which is 0.3 to 4 times higher than the fuel, with the result that a total momentum flux, based on the burner power, of from 1.5 to 8 N/MW and a ratio of the momentum flux densities of the mixture of oxidizing agent and steam to fuel of from 0.8 to 31 are ensured, and as a result a power density of from 0.2 to 0.5 KW/mm is reached at the outlet of the burner block 4.
The mixture of oxidizing agent and steam flows out of the burner mouth 16 at a velocity of from 20 to 80 m/s.
The burner block 4 has a preferably cylindrical opening.
The burner is equipped with a UV light receiver 20 for flame monitoring.
The furnace installation which is diagrammatically depicted in Fig. 3 is used if the furnace off-gases are ladened with dust or other aggressive or oxidation-promoting substances. This furnace installation comprises the refractory lining 1, which surrounds a combustion chamber and has an off-gas opening 19, and the stack 2, which is designed to discharge the furnace off-gas and contains the heat exchanger 8, as well as the burner block 4 with burner 5, burner 5 being connected to the injector 6 and to the heat exchanger 8 by a pipeline 7. The exhaust gases which flow out of the combustion chamber through the off-gas opening 19 are cooled as they flow around the heat exchanger 8, which is supplied with carbon dioxide, and then flow out of the furnace installation through the stack 2.
Liquid or preferably gaseous carbon dioxide which is supplied through the inlet 9 of the heat exchanger 8 is heated to 20°C to 900°C through heat exchange with the furnace off-gas flowing around the heat exchanger 8 and flows through the outlet 10 into the injector 6 at position 13.
The gaseous oxygen, which is used as oxidizing agent at a temperature of from -20 to 4O0C and a pressure of from 0.2 to 40 bar, is fed to the injector 6 through the inlet 11. The oxygen flowing through the injector 6 expands as it flows out of the outflow nozzle 12 of the injector, so that its flow velocity is increased to from 20 to 340 m/s, with the result that a reduced pressure is generated in the injector 6 at position 13, the sucking action of which reduced pressure sucks the carbon dioxide into the oxygen jet, with the carbon dioxide being mixed with the oxygen jet, with temperature balancing, in the pipeline 7, which is designed as a mixing section with a length x, and then the mixture of oxygen and carbon dioxide flows, at a temperature of from 20 to 16000C, through connection 14 into the burner 5, which is supplied via a further connection 15 with natural gas as gaseous fuel.
The pipelines carrying the oxygen and the carbon dioxide consist of a heat- resistant and corrosion-resistant NiCr or ODS alloy and are provided on the inner side with a thermal protection and/or on the outer side with a thermal insulation, e.g. comprising ceramic fibres.
The burner 5, which is used as a parallel-flow burner, advantageously has an inner tube and an outer tube, with natural gas used as gaseous fuel being fed to the burner mouth 16 through the fuel tube 18, which is arranged as the inner tube, and the mixture of oxygen and carbon dioxide being fed to the burner mouth 16 through the outer tube, which accommodates the fuel tube 18 and is designed as an annular gap 21, producing a long, soft and visible burner flame 17 with a flame temperature of from 800-2700°C in the combustion chamber of the furnace installation for heating material that is to be treated.
Partial self-carburization of the fuel takes place in the fuel tube 18 of the burner 5 through recuperative heat exchange with the mixture of oxidizing agent and carbon dioxide.
The burner design according to the invention allows the mixture of oxidizing agent and carbon dioxide to flow out of the burner mouth 16 of the burner at a velocity which is 0.3 to 4 times higher than the fuel, with the result that a total momentum flux, based on the burner power, of from 1.5 to 8 N/MW and a ratio of the momentum flux densities of the mixture of oxidizing agent and carbon dioxide to fuel of from 0.8 to 31 are ensured, and as a result a power density of from 0.2 to 0.5 KW/mm2 is reached at the outlet of the burner block 4.
The mixture of oxidizing agent and carbon dioxide flows out of the burner mouth 16 at a velocity of from 20 to 80 m/s.
The burner block 4 has a preferably cylindrical opening.
The burner is equipped with a UV light receiver 20 for flame monitoring.
List of designations
Refractory lining
Stack (furnace off-gas)
Pipeline (furnace off-gas)
Burner block
Burner
Injector
Pipeline
Heat exchanger
Inlet (8)
Outlet (8)
Inlet (6)
Outflow nozzle (6)
Position (6)
Connection (5)
Connection (5)
Burner mouth
Burner flame
Fuel tube
Off-gas opening
UV light receiver
Annular gap

Claims

Patent claims
1. Process for low-NOx combustion with at least one burner (5) using fuel and oxidizing agent and/or furnace off-gas and/or carbon dioxide and/or steam.
2. Process according to Claim 1, characterized in that the oxidizing agent and/or the furnace off-gases and/or the carbon dioxide and/or the steam are fed to the burner (5) as a mixture.
3. Process according to Claim 1 or 2, characterized in that the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide and/or steam which is fed to the burner (5) is preferably produced by means of at least one injector (6).
4. Process according to one of the preceding claims, characterized in that the injector (6) is preferably operated with the oxidizing agent or fuel.
5. Process according to one of the preceding claims, characterized in that a mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide and/or steam with an oxygen content of at least 5% by volume of oxygen is fed to the burner (5).
6. Process according to one of the preceding claims, characterized in that the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide and/or steam which is fed to the burner (5) is at a temperature of from 20° C to 16000C.
7. Process according to one of the preceding claims, characterized in that the oxidizing agent used is oxygen or an oxygen-containing medium containing at least 10% by volume of oxygen at a pressure of from 0.2 to 40 bar and a temperature of from -20 to 4O0C.
8. Process according to one of the preceding claims, characterized in that the combustion is carried out at a flame temperature of from 8000C to 27000C.
9. Process according to one of the preceding claims, characterized in that the velocity at which the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO2) and/or steam emerges at the burner mouth (16)
. is between 20 and 80 m/s.
10. Process according to one of the preceding claims, characterized in that: a) the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO2) and/or steam flows out of the burner mouth (16) of the burner (5) at a velocity which is 0.3 to 4 times higher than the fuel b) a total momentum flux, based on the burner power, of from 1.5 to 8 N/MW is established c) a ratio of the momentum flux densities of the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO2) and/or steam to fuel is from 0.8 to 31 d) in that a power density of from 0.2 to 0.5 KW/mm2 is reached at the outlet of the burner block (4).
11. Process according to one of the preceding claims, characterized in that partial self-carburization of the fuel takes place in the fuel tube (18) of the burner
(5) through recuperative heat exchange with the mixture of oxidizing agent and/or furnace off-gases and/or carbon dioxide (CO2) and/or steam.
12. Process according to one of the preceding claims, characterized in that the oxidizing agent or fuel flows out of the outflow nozzle (12) of the injector
(6) at a velocity of from 20 to 660 m/s.
13. Apparatus for carrying out the low-NOx combustion with at least one burner, which is arranged in a burner block of a furnace wall surrounding the combustion chamber and is supplied with oxidizing agent and fuel, as described in one of the preceding claims, characterized in that the burner (5) is connected by means of a line (7) to an injector (6) and a heat exchanger (8).
14. Apparatus according to Claim 13, characterized in that the injector (6) has an axially displaceable outflow nozzle (12).
15. Apparatus according to one of the preceding claims, characterized in that the heat exchanger (8) is preferably arranged in a stack (2) which discharges the furnace off-gases from the combustion chamber.
16. Apparatus according to Claim 15, characterized in that the heat exchanger (8) is preferably designed as a recuperator or regenerator. *
17. Apparatus according to one of the preceding claims, characterized in that the injector (6) is arranged in the pipeline (J).
18. Apparatus according to one of the preceding claims, characterized in that the injector (6) and/or the heat exchanger (8) are arranged in the burner (5).
19. Apparatus according to one of the preceding claims, characterized in that the burner (5) has at least one connection (14) for supplying the oxidizing-agent mixture and at least one connection (15) for supplying the fuel.
20. Apparatus according to Claim 19, characterized in that the fuel feed and/or oxidizing-agent mixture feed (18, 21) of the burner (5) are arranged substantially coaxially with respect to one another.
21. Apparatus according to Claim 19 or 20, characterized in that the burner (5) is arranged opposite the off-gas opening (19).
22. Apparatus according to one of the preceding claims, characterized in that the burner (5) is arranged on the off-gas side of the furnace installation, preferably in the off-gas opening (19) or in the stack (2).
23. Apparatus according to one of the preceding claims, characterized in that the media-carrying lines consist of a heat-resistant and corrosion-resistant NiCr or ODS alloy.
24. Apparatus according to Claim 20, characterized in that the media-carrying lines have a thermal insulation on the outer side and/or a thermal protection on the inner side, preferably consisting of ceramic fibres or ceramic block.
25. Apparatus according to one of the preceding claims, characterized in that the burner block (4) which includes the burner (5) preferably has a cylindrical opening.
26. Apparatus according to one of the preceding claims, characterized in that the burner (5) is equipped with a UV light receiver (20) for flame monitoring.
27. Use of the apparatus and process according to one of the preceding claims in a melting or holding furnace, preferably in an aluminium holding furnace or rotary drum furnace or glass-melting furnace.
EP05797772A 2005-10-28 2005-10-28 Process and apparatus for low-nox combustion Withdrawn EP1943461A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2005/011562 WO2007048428A1 (en) 2005-10-28 2005-10-28 Process and apparatus for low-nox combustion

Publications (1)

Publication Number Publication Date
EP1943461A1 true EP1943461A1 (en) 2008-07-16

Family

ID=36577452

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05797772A Withdrawn EP1943461A1 (en) 2005-10-28 2005-10-28 Process and apparatus for low-nox combustion

Country Status (9)

Country Link
US (1) US20090120338A1 (en)
EP (1) EP1943461A1 (en)
JP (1) JP4950208B2 (en)
KR (1) KR101215229B1 (en)
CN (1) CN101297157B (en)
AU (1) AU2005337795A1 (en)
BR (1) BRPI0520661A2 (en)
CA (1) CA2627016C (en)
WO (1) WO2007048428A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3858952A1 (en) 2020-01-31 2021-08-04 Garden's Best GmbH Method and device for separating solid fuels by thermal decomposition by partial oxidation

Families Citing this family (51)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2887322B1 (en) * 2005-06-15 2007-08-03 Alstom Technology Ltd CIRCULATING FLUIDIZED BED DEVICE WITH OXYGEN COMBUSTION FIREPLACE
US20070269755A2 (en) * 2006-01-05 2007-11-22 Petro-Chem Development Co., Inc. Systems, apparatus and method for flameless combustion absent catalyst or high temperature oxidants
EP1995543A1 (en) * 2007-05-10 2008-11-26 AGC Flat Glass Europe SA Heat exchanger for oxygen
FR2927327B1 (en) * 2008-02-08 2010-11-19 Saint Gobain FURNACE LOW NOX WITH HIGH HEAT TRANSFER
US8479720B1 (en) 2008-10-16 2013-07-09 Oscar Enrique Figueroa Heating device and method
CA2646171A1 (en) * 2008-12-10 2010-06-10 Her Majesty The Queen In Right Of Canada, As Represented By The Minist Of Natural Resources Canada High pressure direct contact oxy-fired steam generator
US8858223B1 (en) * 2009-09-22 2014-10-14 Proe Power Systems, Llc Glycerin fueled afterburning engine
JP5509785B2 (en) 2009-10-23 2014-06-04 株式会社Ｉｈｉ Combustion equipment and combustion method for regenerative burner
US9896735B2 (en) * 2009-11-26 2018-02-20 Linde Aktiengesellschaft Method for heating a blast furnace stove
US9863013B2 (en) * 2011-02-22 2018-01-09 Linde Aktiengesellschaft Apparatus and method for heating a blast furnace stove
US20120214115A1 (en) * 2011-02-22 2012-08-23 Cameron Andrew M Method for heating a blast furnace stove
EP2527772B1 (en) * 2011-05-25 2017-11-15 Linde Aktiengesellschaft Heating apparatus
US9851103B2 (en) 2011-12-15 2017-12-26 Honeywell International Inc. Gas valve with overpressure diagnostics
US9835265B2 (en) 2011-12-15 2017-12-05 Honeywell International Inc. Valve with actuator diagnostics
US9995486B2 (en) 2011-12-15 2018-06-12 Honeywell International Inc. Gas valve with high/low gas pressure detection
US9557059B2 (en) 2011-12-15 2017-01-31 Honeywell International Inc Gas valve with communication link
US9846440B2 (en) 2011-12-15 2017-12-19 Honeywell International Inc. Valve controller configured to estimate fuel comsumption
US9234661B2 (en) * 2012-09-15 2016-01-12 Honeywell International Inc. Burner control system
US10422531B2 (en) 2012-09-15 2019-09-24 Honeywell International Inc. System and approach for controlling a combustion chamber
JP6050663B2 (en) * 2012-11-27 2016-12-21 光洋サーモシステム株式会社 Exhaust gas combustion equipment
CN103245054B (en) * 2013-05-31 2015-10-07 新奥科技发展有限公司 A kind of high-temperature gas fuel injector
FR3015636B1 (en) * 2013-12-23 2019-05-31 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude COMBUSTION WITH IMPROVED HEAT RECOVERY
FR3015637B1 (en) * 2013-12-23 2016-01-22 Air Liquide COMBUSTION METHOD AND INSTALLATION WITH OPTIMIZED ENERGY RECOVERY
CN103760295B (en) * 2014-01-21 2016-02-03 上海化工研究院 The material pyrophorisity proving installation of internal heat exchange type band cutter security control assembly
US9638413B2 (en) 2014-03-05 2017-05-02 Progreen Labs, Llc Treatment device of a heating system
US9488373B2 (en) 2014-03-06 2016-11-08 Progreen Labs, Llc Treatment device of a heating system
US9593857B2 (en) * 2014-03-07 2017-03-14 ProGreen Labs, LLC. Heating system
JP6541050B2 (en) * 2014-04-28 2019-07-10 日本ファーネス株式会社 High temperature oxygen combustion apparatus and high temperature oxygen combustion method
US10281140B2 (en) 2014-07-15 2019-05-07 Chevron U.S.A. Inc. Low NOx combustion method and apparatus
US9645584B2 (en) 2014-09-17 2017-05-09 Honeywell International Inc. Gas valve with electronic health monitoring
US9417124B1 (en) * 2015-05-13 2016-08-16 Honeywell International Inc. Utilizing a quench time to deionize an ultraviolet (UV) sensor tube
CN108603658A (en) * 2016-03-15 2018-09-28 杰伊·凯勒 Non- premixed swirl burner end and combustion strategies
JP6242453B1 (en) * 2016-08-25 2017-12-06 中外炉工業株式会社 Heating furnace cooling system
US10684040B2 (en) * 2016-08-25 2020-06-16 Fire Chief Industries LLC Furnace
EP3290794A1 (en) * 2016-09-05 2018-03-07 Technip France Method for reducing nox emission
DE102016117252A1 (en) * 2016-09-14 2018-03-15 Horn Glass Industries Ag Method for operating a burner and firing device
US10564062B2 (en) 2016-10-19 2020-02-18 Honeywell International Inc. Human-machine interface for gas valve
EA032968B1 (en) * 2017-02-17 2019-08-30 Сергей Михайлович Кабишов Method for environment-friendly burning of hydrocarbon fuel
AT520131A2 (en) * 2017-07-13 2019-01-15 Andritz Tech & Asset Man Gmbh METHOD FOR REDUCING NITROGEN OXIDE IN BAND TREATMENT OVENS
AT520134B1 (en) * 2017-07-13 2020-03-15 Andritz Tech & Asset Man Gmbh METHOD FOR REDUCING NITROGEN OXIDES IN TAPE TREATMENT OVENS
US10801738B2 (en) 2017-08-09 2020-10-13 Fire Chief Industries LLC Furnace
US20190113223A1 (en) * 2017-10-18 2019-04-18 L'Air Liquide, Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude METHOD FOR MINIMIZING NOx EMISSIONS DURING POX BASED SYNGAS PLANT STARTUP
CN107702117B (en) * 2017-10-30 2023-11-14 北京航化节能环保技术有限公司 Combustor for preparing reducing gas by secondary stoichiometric burning
US11073281B2 (en) 2017-12-29 2021-07-27 Honeywell International Inc. Closed-loop programming and control of a combustion appliance
US10648857B2 (en) 2018-04-10 2020-05-12 Honeywell International Inc. Ultraviolet flame sensor with programmable sensitivity offset
US12117169B2 (en) 2018-04-26 2024-10-15 Technip France Burner system for a steam cracking furnace
US10697815B2 (en) 2018-06-09 2020-06-30 Honeywell International Inc. System and methods for mitigating condensation in a sensor module
CN108975915B (en) * 2018-08-23 2021-05-18 索通发展股份有限公司 Process for producing prebaked anode with ultralow emission
KR102077710B1 (en) * 2018-09-28 2020-02-17 한국생산기술연구원 Internal recirculation type oxy-fuel combustor
US10739192B1 (en) 2019-04-02 2020-08-11 Honeywell International Inc. Ultraviolet flame sensor with dynamic excitation voltage generation
CN114060831A (en) * 2021-11-19 2022-02-18 屹泰柯环保科技(上海)有限公司 Dual-fuel direct-fired incinerator system

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0482508U (en) * 1990-11-19 1992-07-17

Family Cites Families (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2800175A (en) * 1949-06-11 1957-07-23 Libbey Owens Ford Glass Co Firing tank furnaces
JPS583216B2 (en) * 1974-08-20 1983-01-20 キヤノン株式会社 Automatic focusing method
JPS51115335A (en) * 1975-04-03 1976-10-09 Kawasaki Heavy Ind Ltd Exhaust gas circulation device of combustion system
JPS56140736A (en) * 1980-04-03 1981-11-04 Nippon Telegr & Teleph Corp <Ntt> Method and device for testing data transmission circuit line
US4445842A (en) * 1981-11-05 1984-05-01 Thermal Systems Engineering, Inc. Recuperative burner with exhaust gas recirculation means
JPS6011008A (en) * 1983-07-01 1985-01-21 Ebara Corp Combustion device for heater
US4800866A (en) * 1987-03-13 1989-01-31 Bloom Engineering Company, Inc. Low NOX radiant tube burner and method
DE3830038A1 (en) * 1988-09-03 1990-03-08 Gaswaerme Inst Ev Burner and method for its operation
JPH0346739A (en) * 1989-07-14 1991-02-28 Hitachi Ltd Plasma x-ray generator
CH680157A5 (en) * 1989-12-01 1992-06-30 Asea Brown Boveri
US4986748A (en) * 1989-12-15 1991-01-22 Corning Incorporated Wide range oxy-fuel burner and furnace operation
DE9005563U1 (en) * 1990-05-16 1990-07-19 Körting Hannover AG, 3000 Hannover burner
ES2064538T3 (en) * 1990-06-29 1995-02-01 Wuenning Joachim PROCEDURE AND DEVICE FOR COMBUSTION OF FUEL IN A COMBUSTION ENCLOSURE.
JP2570474B2 (en) * 1990-07-24 1997-01-08 コクヨ株式会社 Board mounting structure
JP3068888B2 (en) * 1991-05-28 2000-07-24 株式会社日立製作所 Combustion apparatus and operation method thereof
US5413477A (en) * 1992-10-16 1995-05-09 Gas Research Institute Staged air, low NOX burner with internal recuperative flue gas recirculation
US5269679A (en) * 1992-10-16 1993-12-14 Gas Research Institute Staged air, recirculating flue gas low NOx burner
JPH0727325A (en) * 1993-07-09 1995-01-27 Mitsubishi Heavy Ind Ltd Method for preventing clogging with caulking at burner gun
DE69735965T2 (en) * 1996-07-19 2007-01-04 Babcock-Hitachi K.K. burner
JPH10103617A (en) * 1996-09-28 1998-04-21 Osaka Gas Co Ltd Discharged gas recirculating system for furnace
US6071116A (en) * 1997-04-15 2000-06-06 American Air Liquide, Inc. Heat recovery apparatus and methods of use
US8979525B2 (en) * 1997-11-10 2015-03-17 Brambel Trading Internacional LDS Streamlined body and combustion apparatus
US6206686B1 (en) * 1998-05-01 2001-03-27 North American Manufacturing Company Integral low NOx injection burner
FR2782780B1 (en) * 1998-09-02 2000-10-06 Air Liquide COMBUSTION METHOD FOR BURNING A FUEL
JP3589389B2 (en) * 1998-12-28 2004-11-17 株式会社オットー Low NOX radiant tube burner
US6383462B1 (en) * 1999-10-26 2002-05-07 John Zink Company, Llc Fuel dilution methods and apparatus for NOx reduction
JP2001165578A (en) * 1999-12-03 2001-06-22 Chugai Ro Co Ltd Aluminum melting furnace
EP1132684A3 (en) * 2000-03-10 2002-05-02 L'air Liquide, S.A. à Directoire et Conseil de Surveillance pour l'Etude et l'Exploitation des Procédés Georges Claude Method and system for lancing gas into an environment with variable entrainment of non-lanced gas
CN1126907C (en) * 2001-09-21 2003-11-05 清华大学 Industrial furnace with high-temperature low-oxygen air burner
JP2004125380A (en) * 2002-07-29 2004-04-22 Miura Co Ltd Low nox combustion device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0482508U (en) * 1990-11-19 1992-07-17

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3858952A1 (en) 2020-01-31 2021-08-04 Garden's Best GmbH Method and device for separating solid fuels by thermal decomposition by partial oxidation

Also Published As

Publication number Publication date
WO2007048428A1 (en) 2007-05-03
AU2005337795A1 (en) 2007-05-03
BRPI0520661A2 (en) 2009-05-19
CA2627016A1 (en) 2007-05-03
CN101297157A (en) 2008-10-29
JP4950208B2 (en) 2012-06-13
KR20080069970A (en) 2008-07-29
CN101297157B (en) 2013-01-16
JP2009513920A (en) 2009-04-02
KR101215229B1 (en) 2012-12-26
CA2627016C (en) 2013-08-20
US20090120338A1 (en) 2009-05-14

Similar Documents

Publication Publication Date Title
CA2627016C (en) Process and apparatus for low-nox combustion
US6036476A (en) Combustion apparatus
KR970009482B1 (en) METHOD AND APPARATUS FOR OXY-FUEL HEATING WITH LOWERED NOx IN HIGH TEMPERATURE CORROSIVE ENVIRONMENTS
US9651248B2 (en) Method for generating combustion by means of a burner assembly and burner assembly therefore
SU955866A3 (en) Apparatus for feeding and burning additional fuel in shaft furnace
JP4440646B2 (en) Method for thermometallurgical treatment of metal, metal melt and / or slag, and injector device
JPS6214048B2 (en)
CN104121581A (en) Efficient low-NOx tube type heating furnace low-concentration oxygen-enriched combustion system and combustor
CN101874180A (en) Flameless thermal oxidation apparatus and methods
AU2010329886B2 (en) Burner unit for steel making facilities
EP0328418A1 (en) Radiant tube furnace and method of burning a fuel
CN102794444A (en) Heating method and system for controlling air ingress into enclosed spaces
US8992210B2 (en) Method and device for diluted combustion
JP2004091921A (en) Method for blowing solid fuel into blast furnace and blown lance
SU1728581A1 (en) Method of burning gaseous fuel
DE102004034211A1 (en) Method for NOx-low combustion especially in furnaces operates with burner using fuel and oxidation agent or furnace waste gas supplied as mixture to burner
JP2023031404A (en) Blast furnace tuyere burner
EP1537371A1 (en) Method and burner for rotary kilns
JPH05248605A (en) Radiant tube type heater device and method of combustion in heater device
JPS59159924A (en) Combustion heating furnace and heating method without causing oxidation utilizing said furnace
JPH0518509A (en) Apparatus and method for controlling flame in boiler combustion chamber

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20080424

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

DAX Request for extension of the european patent (deleted)
GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

INTG Intention to grant announced

Effective date: 20160713

GRAJ Information related to disapproval of communication of intention to grant by the applicant or resumption of examination proceedings by the epo deleted

Free format text: ORIGINAL CODE: EPIDOSDIGR1

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

INTC Intention to grant announced (deleted)
INTG Intention to grant announced

Effective date: 20160908

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20170119