EP3940293A1 - Procédé de combustion étagée d'un combustible et tête de combustion - Google Patents

Procédé de combustion étagée d'un combustible et tête de combustion Download PDF

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Publication number
EP3940293A1
EP3940293A1 EP21182423.0A EP21182423A EP3940293A1 EP 3940293 A1 EP3940293 A1 EP 3940293A1 EP 21182423 A EP21182423 A EP 21182423A EP 3940293 A1 EP3940293 A1 EP 3940293A1
Authority
EP
European Patent Office
Prior art keywords
fuel
combustion
nozzles
primary
burner tube
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.)
Pending
Application number
EP21182423.0A
Other languages
German (de)
English (en)
Inventor
Thomas Schmidt
Kathleen Hanka
Ronny Kretzschmar
Stephan H. Tobias
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.)
Elco Burners GmbH
Original Assignee
Elco Burners GmbH
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 Elco Burners GmbH filed Critical Elco Burners GmbH
Publication of EP3940293A1 publication Critical patent/EP3940293A1/fr
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/02—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
    • 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 
    • F23C5/00—Disposition of burners with respect to the combustion chamber or to one another; Mounting of burners in combustion apparatus
    • 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 
    • F23C5/00—Disposition of burners with respect to the combustion chamber or to one another; Mounting of burners in combustion apparatus
    • F23C5/08—Disposition of burners
    • 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
    • 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
    • F23D—BURNERS
    • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
    • F23D11/36—Details, e.g. burner cooling means, noise reduction means
    • F23D11/40—Mixing tubes or chambers; Burner heads
    • F23D11/404—Flame tubes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
    • F23D11/36—Details, e.g. burner cooling means, noise reduction means
    • F23D11/40—Mixing tubes or chambers; Burner heads
    • F23D11/408—Flow influencing devices in the air tube
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/20—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F23D14/48—Nozzles
    • F23D14/58—Nozzles characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F23D14/60—Devices for simultaneous control of gas and combustion air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F23D14/62—Mixing devices; Mixing tubes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F23D14/70—Baffles or like flow-disturbing devices
    • 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
    • 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 
    • F23C2202/00—Fluegas recirculation
    • F23C2202/40—Inducing local whirls around flame
    • 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
    • F23C2900/03005—Burners with an internal combustion chamber, e.g. for obtaining an increased heat release, a high speed jet flame or being used for starting the combustion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2203/00—Gaseous fuel burners
    • F23D2203/007—Mixing tubes, air supply regulation

Definitions

  • the present invention relates to a method for the staged combustion of a fuel and a combustion head for the staged combustion of a fuel.
  • nitrogen oxides e.g. NO, NO2
  • NO nitrogen oxides
  • the thermal NO is dependent on the so-called Zeldovich mechanism on the one hand on the residence time of the reactants in the combustion zone and on the other hand to a large extent on the combustion temperature itself.
  • the combustion temperature is linked to the fuel/air ratio ⁇ .
  • a fuel/air ratio of ⁇ ⁇ 1 is referred to as a rich mixture; there is too much fuel.
  • a fuel/air ratio ⁇ > 1 is referred to as a lean mixture, there is excess air. In both cases, the combustion temperature drops again and consequently less thermal NO is formed.
  • the formation of prompt NOx also plays a not insignificant role.
  • the prompt NO arises from hydrocarbon radicals CH formed as intermediates in flames, which are present as intermediate products during the combustion of carbonaceous fossil fuels.
  • the CH radicals react with atmospheric nitrogen to form hydrocyanic acid (HCN), which is further converted to NO in very rapid formation reactions.
  • HCN hydrocyanic acid
  • a proven method to suppress the formation of free CH radicals and thus the formation of prompt NO is lean combustion or lean combustion.
  • Lean combustion refers to combustion with excess air, i.e. with ⁇ > 1.
  • the prompt NO is formed in small amounts compared to the thermal NO, but is also crucial for the reduction of the NO formation, especially in ultra-low NO applications.
  • EP 1 754 937 B1 and EP 2 037 173 B1 show burner heads with which NO reduction is achieved. These are primarily single-stage combustion processes that only allow further NO optimization and flame stabilization to a limited extent.
  • DE 195 09 219 A1 shows a combustor for two-stage combustion with a hyper-stoichiometric air-gas mixture in the first stage and a sub-stoichiometric air-gas mixture in the second stage.
  • a mixing zone Different fluids that are not (yet) burned are mixed in a mixing zone.
  • the conditions that must be present for combustion are usually not met. This can be the case, for example, when the flow rate of the ignitable mixture is significantly higher than the flame speed.
  • a combustion zone is an area where the conditions required for combustion exist.
  • a combustion zone exists when an ignitable mixture (eg, fuel-combustion air mixture, fuel-combustion air-exhaust mixture, fuel-oxidant mixture, fuel-oxidant-exhaust mixture) is present, the flow rate of the ignitable mixture, and the flame velocity are essentially the same and have a temperature that is equal to or greater than the ignition temperature of the ignitable mixture.
  • oxidizing agent includes the term combustion air, but also includes, for example, ambient air enriched with additional oxygen. Ignition or combustion cannot take place in areas where these conditions are not met. Mixed zones often merge into combustion zones without any clear spatial separation.
  • Multi-stage combustion processes have been known in practice for a long time. At present, however, the approaches known to date are not sufficient to be able to continue to meet the steadily increasing NO requirements for the operation of combustion plants in the long term. A more intensive NO reduction is possible through a staged combustion according to the disclosure. With appropriate controllability, the NO reduction can also be guaranteed over a wide load range and/or for different fuels and/or for different combustion chambers.
  • a method for the staged combustion of a fuel while supplying combustion air into a burner tube according to claim 1 is provided.
  • the fuel can be a gas or a liquid fuel.
  • a first quantity of fuel is introduced to form a primary flame within the burner tube.
  • a second amount of fuel may be added downstream to form a main flamefront.
  • the main flame stabilizes downstream of the burner tube and spaced from the burner tube.
  • the fuel feeds are designed in such a way that the primary flame burns with a stoichiometry greater than 1.5, in particular greater than 2.0. This allows a very low flame temperature to be achieved. It forms practically none prompt NO.
  • the main flame is slightly lean of stoichiometry.
  • the stoichiometry can be between 1.03 ... 1.18.
  • the temperature of the main flame can be significantly reduced by flue gases recirculated inside the combustion chamber.
  • the first amount of fuel may be regulated independently of the second amount of fuel.
  • a hyper-stoichiometric primary flame can thus be guaranteed over a wide load range.
  • the first amount of fuel supplied can be significantly less than the second amount of fuel supplied.
  • the first amount of fuel can be between 3% and 15% of the total amount of fuel, i.e. the sum of the first amount of fuel and the second amount of fuel.
  • the first amount of fuel is preferably between 5% and 10% of the sum of the first amount of fuel and the second amount of fuel.
  • part of the combustion air is twisted. This creates turbulent combustion air. A first partial quantity of the first quantity of fuel is released into the area of the air turbulence. This creates a turbulent lean air/fuel mixture. Very thorough mixing can be achieved. In this range, the flow velocity is high and the mixture is lean, so that there are no ignition conditions. The flow rate of the swirled lean air/fuel mixture is reduced in the next step. A second portion of the first amount of fuel is introduced into the decelerated swirled lean air/fuel mixture.
  • a combustor for staged combustion of a fuel according to claim 7.
  • the burner head provided enables the procedure to be carried out.
  • the combustor is configured to combust a first supplied amount of fuel in a lean-of-stoichiometric primary flame.
  • a second quantity of fuel supplied is combusted in a slightly over-stoichiometric main flame.
  • a supply of the first quantity of fuel and a supply of the second quantity of fuel can preferably be regulated independently of one another and thus ensure combustion with a very low level of nitrogen oxides over a wide load range.
  • the burner head 10 comprises a burner tube 12, a swirl device 14, first fuel nozzles 16a, 16b, second fuel nozzles 18, a first fuel feed 20 and a second fuel feed 22. Arrows symbolize the inflowing fuel.
  • a lean primary flame 24 forms within the swirler 14 and a main flame or main flame front 26 spaced from the combustor 10, both of which are defined by a flame in the 1 are represented symbolically.
  • Combustion head 10 thus serves to burn fuel in stages.
  • the fuel can be gaseous.
  • the fuel can be natural gas.
  • the fuel may include hydrogen.
  • a dual-fuel burner is also possible, in which liquid fuel can also be burned in addition to gaseous fuel.
  • a liquid fuel only burner is also possible.
  • the further description generally relates to an embodiment as a gas burner in a non-limiting manner.
  • the burner tube 12 is shown in the illustration 1 Combustion air 28 supplied from the right.
  • the end of the burner tube 12 on the right in the illustration is therefore the upstream end.
  • the combustor tube 12 may be substantially cylindrical.
  • the combustion air 28 flows through the burner tube 12 and leaves it at the open end of the burner tube 12 on the left in the illustration, the downstream end.
  • the main flame front 26 is formed downstream of the combustion head 10.
  • the combustion chamber or furnace not shown.
  • the amount of fuel from the first fuel nozzles 16a, 16b may be small in relation to the amount of fuel exiting the second fuel nozzles 18. If only a small amount of fuel is burned well lean of stoichiometry in the primary flame 24, a second lean of stoichiometry combustion stage is not necessary. Therefore, the spaced main flame 26 can also be overall lean of stoichiometry.
  • a general under-stoichiometric combustion zone as in the case of staged combustion with under-stoichiometric and over-stoichiometric combustion zones and the residence time of the gases in these zones necessary for NO reduction, is not produced with the combustion head 10 according to the invention.
  • the inventive method provides a heavily over-stoichiometric primary flame and a slightly over-stoichiometric main flame.
  • the swirl device 14 is arranged within the burner tube 12 .
  • the twister 14 can be open at both ends.
  • a longitudinal axis of the burner tube 12 and a longitudinal axis of the swirl device 14 can be parallel to one another or lie on top of one another, so that the swirl device 14 is located centrally in the burner tube 12 and is radially evenly spaced from the inner wall of the burner tube.
  • Part of the combustion air 28 flows outside the swirl device 14 through the burner tube 12, another part of the combustion air 28 flows through the swirl device 14.
  • the swirl device 14 comprises a swirl body 30, swirl vanes 32 and a perforated partition 34.
  • the swirl body 30 can be essentially cylindrical.
  • the perforated dividing wall 34 can run essentially perpendicularly to the longitudinal axis of the swirl body 30 and divide an interior space of the swirl body 30 into a first area 36 and a second area 38 .
  • the first region 36 may be upstream of the second region 38 .
  • the broken partition wall 34 can cause a pressure loss. It can thus locally reduce the flow speed downstream of the partition wall 34 that has been perforated.
  • the swirl vanes 32 can only be arranged in the first region 36 .
  • the second area downstream of the partition wall 34 can be free of swirl vanes 32 .
  • a plurality of swirl vanes 32 can be provided.
  • the swirl body 30 can have a larger diameter in the first area 36 than in the second area 38. In the transition between the first area 36 and the second area 38, a conical section can be provided.
  • the first fuel nozzles 16a, 16b are arranged inside the swirl body 30. You are connected to the first fuel feed 20 .
  • the first fuel supply 20 permits regulation of the amount of fuel/combustion gas flowing to the first fuel nozzles 16a, 16b, as indicated by a symbol 40 in 1 shown. This control is separate and independent of a control 42 in the second fuel feed 22.
  • the first fuel nozzles 16a, 16b can include primary fuel nozzles, also referred to below as primary gas nozzles, 16a, which are located in the second, downstream region 38 of the swirl device 14.
  • the first fuel nozzles 16a, 16b can include further fuel nozzles--hereinafter referred to as auxiliary fuel nozzles or auxiliary gas nozzles 16b--which are located in the first, upstream region 36 of the swirl device 14.
  • the support fuel nozzles 16b can be distributed evenly between the swirl vanes 32 .
  • the auxiliary fuel nozzles 16b can be arranged essentially parallel to a longitudinal axis of the burner tube 12 .
  • the swirl vanes 32 cause a strong turbulence of the combustion air 28.
  • the fuel flowing out of the support fuel nozzles 16b which is also referred to as support gas, is thus highly efficiently premixed with part of the combustion air 28 for the primary flame 24.
  • a twisted fuel/combustion air mixture is created.
  • the fuel supply through the auxiliary fuel nozzles 16b can be designed in such a way that a turbulent lean air/fuel mixture is formed.
  • the auxiliary fuel nozzles 16b can deliver a first subset of the first quantity of fuel.
  • the auxiliary fuel nozzles 16b can have bores for dispensing the fuel.
  • the bores can be arranged in such a way that the fuel is discharged at least partially inwards in a substantially radial direction, i.e. in a direction substantially perpendicular to the wall of the swirler 30. Due to the high flow velocities of the swirled combustion air and due to the high proportion of air in the ratio The ignition conditions of the swirled fuel/combustion air mixture in the region of the swirl vanes 32, ie in the upstream region 36, are not yet given in relation to the fuel or gas quantity.
  • the partition wall 34 can be designed to decelerate the swirled fuel/combustion air mixture.
  • the partition wall 34 can have openings for this purpose.
  • the dividing wall can be configured essentially in the manner of a lattice.
  • a geometry of the dividing wall 34 can be designed to reduce the flow velocity of the swirled fuel/combustion air mixture while leaving the turbulence largely undisturbed.
  • the partition 34 reduces the absolute flow rate of the swirled and premixed primary air and thus ensures the ignition of the primary flame 24, which is additionally enriched in this area with a second portion of the first amount of fuel.
  • the primary fuel nozzles 16a may be evenly distributed in the downstream area 38 .
  • the primary fuel nozzles 16a are thus located downstream of the partition wall 34 in an area with a lower flow velocity.
  • the primary fuel nozzles 16a may be arranged substantially perpendicular to a longitudinal axis of the combustor tube 12 .
  • the primary fuel nozzles 16a can be evenly distributed in a corona.
  • a plurality of primary fuel nozzles 16a may be provided.
  • the primary fuel nozzles 16a deliver the second part of the first quantity of fuel, which is referred to as the primary gas, to the fuel-air mixture formed in the bladed part of the swirl body 30 or, in other words, in the first region 36, and thus produce the ignitable mixture for the formation of the primary flame 24.
  • the primary fuel nozzles 16a can have bores for dispensing the fuel.
  • the bores can be arranged laterally on the primary fuel nozzles 16a.
  • the lateral bores can be arranged in such a way that the fuel is discharged essentially in a tangential direction.
  • the ratio of the opening area of the entirety of the bores in the primary fuel nozzles 16a to the opening area of the entirety of the bores in the support fuel nozzles 16b can determine a ratio of primary gas to support gas, taking into account the supply lines to the primary fuel nozzles 16a and the support fuel nozzles 16b.
  • the ratio can be chosen depending on the overall geometry and the fuel quality or the fuel composition.
  • the ratio can be around 1:1.
  • About half of the fuel flowing through first fuel guide 20 may be delivered via primary fuel nozzles 16a in region 38, and about half of the fuel flowing through first fuel guide 20 may be delivered via support fuel nozzles 16b in region 36.
  • the separate controllability of the primary and support gas by the control device 40 in relation to the controllability of the second and main fuel quantity flowing through the second fuel supply 22 and the design of the swirler 30, primary and support fuel nozzles 16a, 16b and partition 34 can provide a primary flame 24 with a Generate stoichiometry ⁇ >>1 over a wide load range.
  • the stoichiometry of the primary flame 24 is ⁇ >1.5.
  • the stoichiometry of the primary flame 24 is ⁇ >2.
  • a stable primary flame 24 For a stable primary flame 24, the previous supply of the support gas via the support fuel nozzles 16b into the swirled combustion air and thus the enrichment and premixing of the primary air with fuel, the type and position of the introduction of the primary gas, the ratio of support and primary gas and the geometry and Position of the partition wall 34 in the bladeless part 38 of the swirler 30 in the illustrated embodiment of importance.
  • Other means can be provided in order to achieve a stable primary flame with a stoichiometry greater than 1, in particular greater than 1.5 or even greater than 2.
  • the cylindrical, bladeless part of the swirl body 30, the area 38 in 1 Designed so that the primary flame 24 forms in a defined area that is protected from the remaining combustion air 28 that flows through the burner tube 12 outside of the swirl body 30 .
  • the second fuel nozzles 18, also referred to as main gas nozzles, are located outside and downstream of the swirl device 14.
  • the second fuel nozzles 18 are connected to the second fuel feed 22.
  • the second fuel feed 22 allows the amount of fuel/combustion gas flowing to the second fuel nozzles 18 to be regulated.
  • the second amount of fuel comprises the majority of the total amount of fuel and is therefore also referred to as the main amount of fuel or main gas.
  • the adjustability of the main gas is marked with the symbol 42 in 1 shown.
  • the second fuel nozzles 18 are located within the combustor tube 12.
  • the second fuel nozzles 18 may be located at the downstream end of the combustor tube 12 and terminated therewith.
  • the second fuel nozzles 18 can evenly over the Inner circumference of the burner tube 12 are distributed.
  • an annular delta disk that can fill a gap between burner tube 12 and second fuel nozzles 18 at the downstream end of the burner tube.
  • the delta disc is with reference to Figures 4-6 explained in more detail.
  • the second fuel nozzles 18 can be designed to ensure a high fuel exit velocity.
  • the resulting impulse transports the fuel as far as possible into the combustion chamber and forms a combustion zone spaced apart from the combustion head 10 .
  • the main gas can be discharged essentially in the direction of flow, ie parallel to the longitudinal axis of the burner tube 12 .
  • the second fuel nozzles 18 can have an opening on one end face. A panel can determine the opening at the front.
  • the configuration of the second fuel nozzles 18 results in the formation of the main flame or main flame front 26 which is spaced from the downstream end of the combustion head 10 and is stably formed in the combustion chamber, not shown in detail.
  • the main flame 26 can have a slim and elongated flame shape.
  • An internal exhaust gas recirculation which is explained in more detail below, can inject exhaust gases into the hot zones of the main flame 26 and thus into the areas of greatest NO production. This reduces NO production in the main flame.
  • the fuel feeds can be designed and arranged in such a way that ignition energy for the spaced-apart main flame 26 from the primary flame and recirculated exhaust gases is made available in order to ignite the mixture of main fuel, combustion air or generally oxidant and recirculated exhaust gas and ensure a continuous, stable progression of the ensure oxidation reactions.
  • Both gas connections, ie fuel supply 20 for the primary and supporting gas for the primary flame 24 and fuel supply 22 for the main gas for the main flame 26 are regulated separately by gas control devices 40 and 42 in the embodiment shown.
  • the quantity of gas in the primary flame 24 and in the main flame 26 can be set separately from one another and the stoichiometry in the respective combustion zone can thus be regulated individually. This allows the setting of a stable and over-stoichiometric primary combustion zone and thus the formation of an almost NO-free primary flame 24 over a wide load range and adaptation to different combustion chambers.
  • Combustion head 10a can have the same features as for the in 1 illustrated combustion head 10 described.
  • Combustion head 10a may represent an implementation of combustion head 10 .
  • the same reference numbers are therefore used as in 1 used.
  • the description of 2 is essentially limited to details arising from the presentation of the 1 not emerge. In the 2 the burner tube 12 is not shown.
  • the second fuel feed 22 of the combustion head 10a is designed as a tube which has a connection flange 44 for connection to a fuel supply. Smaller pipes 46 or main gas lances 46 lead from the second fuel feed 22 . The main gas lances 46 direct the fuel from the second fuel feed 22 to the second fuel nozzles 18 and close with them. In the illustrated embodiment, the combustion head 10a has six second fuel nozzles 18 . The main gas lances 46 run outside the swirl body 30.
  • the second fuel feed 22 transitions into a fuel pipe 48 which can run through the swirl body 30 in the middle parallel to the longitudinal axis of the swirl body 30 .
  • the fuel pipe 48 is preferably designed as a central fuel pipe.
  • the fuel tube 48 carries the main gas in the first upstream region. Downstream of where the main gas lances 46 branch off, a gas separating plate 50 seals off the second fuel feed 22 from the subsequent fuel pipe 48 .
  • the gas separating plate 50 is arranged in the second fuel feed 22/the fuel pipe 48 and is essentially perpendicular to a longitudinal axis of the second fuel feed 22/the fuel pipe 48.
  • the first fuel feed 20 opens into the fuel pipe 48. Downstream of the gas separating plate 50, the fuel pipe 48 is therefore used to guide the first quantity of fuel. Smaller tubes 52, the so-called support gas lances, branch off downstream of the gas separating plate 50. The supporting gas lances 52 conduct the fuel from the first fuel feed 20 to the supporting gas nozzles 16b.
  • the combustion head 10a has three supporting gas nozzles 16b. The support gas nozzles 16b are inside the swirl body 30. The swirl vanes 32 can be seen next to the supporting gas nozzle 16b.
  • FIG. 2 An exemplary shape of the swirl body 30 can also be found in FIG.
  • the swirl body 30 In the first area 38 with the swirl vanes 32 and the support gas nozzles 16b, the swirl body 30 is configured cylindrically with a first diameter.
  • the swirl body 30 In the second region 38 without swirl vanes, the swirl body 30 is cylindrical with a second diameter. In one embodiment, the first diameter is larger than the second diameter. Both areas 36, 38 can then be connected to one another by a conical area.
  • Swirl body 30 is displaceably mounted on fuel pipe 48 via a swirl body inner tube 54, which allows, for example, an adjustment to different combustion chamber geometries and process parameters.
  • a swirl body inner tube 54 By axially shifting the Swirl body 30 on the fuel pipe 48, the ratio of the amounts of air which flows through the swirl body 30 and which exits from the gap formed by the outer diameter of the swirler in area 38 and the inner diameter of the delta disc 66 can be influenced within limits.
  • FIG. 3 shows schematically in a perspective view the combustion head 10a from a flame side.
  • FIG. 3 shows schematically in a perspective view the combustion head 10a from a flame side.
  • FIG. 3 shows schematically in a perspective view the combustion head 10a from a flame side.
  • FIG. 3 shows schematically in a perspective view the combustion head 10a from a flame side.
  • FIG. 3 shows schematically in a perspective view the combustion head 10a from a flame side.
  • a direct, electrical ignition 56 can be provided, which is only used initially for (eg for the first time) ignition. Once a flame has formed and stabilized, the fuel-air mixture continues to ignite by reaction from the flame.
  • the ignition device 56 is attached to one of the support gas nozzles 16b.
  • the fuel pipe 48 ends downstream in a cylindrical fuel distributor 58.
  • the fuel distributor 58 can also be referred to as the primary gas distributor 58 since at this point the fuel pipe 48 only carries the primary gas.
  • four primary gas nozzles 16a are arranged radially on a lateral surface of the primary gas distributor 58 on the primary gas distributor 58 .
  • the primary gas nozzles 16a are arranged at equal intervals and point away from the fuel pipe 48 or from the primary gas distributor 58 towards the burner pipe 12 (not shown).
  • the primary gas nozzles 16a can have bores 60 .
  • Each primary gas nozzle 16a can have a plurality of bores 60 . Two bores 60 are shown. However, there can also be more or fewer bores.
  • the bores 60 are arranged on the primary gas nozzles 16a in such a way that the primary gas essentially flows out in a tangential direction.
  • the orientation of the bores 60 can be matched to the arrangement and configuration of the swirl vanes 32 in such a way that the primary gas is discharged with the flow of the fuel/combustion air mixture swirled in the first region 36 .
  • the primary gas flows out of the lateral bores in a tangential direction that is determined by the direction of the swirl.
  • the primary gas nozzles 16a can have an axial bore, from which the primary gas also flows.
  • the second fuel nozzles 18 or main gas nozzles are arranged in a circle around the downstream end of the swirl body 30 . They have holes 62 on their end faces.
  • the bores 62 are designed to ensure a high fuel exit velocity of the main gas, so that the main flame front 26 forms at a distance from the combustion head.
  • Combustion head 10b may correspond to combustion head 10 and/or combustion head 10a.
  • Combustion head 10b may correspond to combustion head 10 and/or combustion head 10a.
  • Figures 1 to 3 illustrated parts will not be described again in detail.
  • parts have been cut away to show details better.
  • the part of the swirl body 30 pointing towards the viewer has been cut away so that the internal structure can be seen is.
  • the area where the first fuel feed 20 opens into the fuel pipe 48 has been cut open.
  • the primary gas nozzles 16a In the side view representation of the 4 holes 64 are visible on the primary gas nozzles 16a.
  • the bores 64 are configured to discharge the fuel substantially radially inward.
  • the primary gas nozzles can also have axial bores.
  • the burner tube 12 is also shown.
  • the combustor tube 12 may be terminated at its downstream end by an annular delta disc 66 extending radially inward from the combustor tube 12 .
  • the delta disc 66 has a plurality of guide devices 68 pointing radially inwards.
  • the openings of the second fuel nozzles 18 can end flush with the delta disc 66 .
  • the design of the delta disc 66 with reference to 6 is described in more detail, is used for internal exhaust gas recirculation in the main flame 26. The recirculation can be effected by the portion of the combustion air 28 that flows past the swirl device 14 and hits the ring of the annular delta disk 66 directly.
  • the amount of fuel from the primary gas nozzles 16a and the support gas nozzles 16b is small in relation to the amount of fuel which exits from the second fuel nozzles 18 . It is preferably 3% to 15%, particularly preferably 5% to 10% of the total amount of fuel.
  • the excess air required for the complete combustion of the partial fuel quantities from the primary gas nozzles 16a, the supporting gas nozzles 16b and from the fuel nozzles 18 can be between 1.075 and 1.2 in embodiments.
  • the combustion zones of the primary flame and the spaced main flame are each lean of stoichiometry. Locally, due to the flow of fuel entering the combustion chamber axially, it can from the second Fuel nozzles 18 come to form sub-stoichiometric zones before fuel gas and air and recirculated exhaust gas have been sufficiently mixed.
  • the reduction in the NO values results from the extremely low-NO combustion in the partially premixed, very lean primary flame in combination with the main flame at a distance, which, due to the intensive mixing in of internally recirculated exhaust gases and the lowering of the O2 partial pressure in the mixture, has no effect on the NO Formation can form harmful high temperatures.
  • the formation of a slim but not too long flame is advantageous, which efficiently decouples the heat released during the combustion of the fuel from the conversion of the chemical enthalpy to the cooled surrounding walls of the combustion chamber through radiation and convection.
  • FIG. 12 schematically shows a sectional view of a front portion of the combustion head 10b.
  • the swirl body inner tube 54 which is routed over the fuel tube 48, is visible.
  • the swirl body can thus be displaced longitudinally and can be fixed in its position with a screw 70 .
  • the displaceability allows better adaptation to different combustion chambers in which the main flame front 26 is formed.
  • the perforated partition 34 is arranged in the area 38 .
  • the breached partition 34 is positioned and configured such that the primary flame 24 is securely stabilized or retained within the region 38 of the swirler 30 in the described embodiment.
  • Fig. 12 schematically shows a front view of the combustion head 10b from the flame side, or in other words from the combustion chamber.
  • the fuel distributor 58 from which the primary gas nozzles 16a with their bores 60 extend.
  • the perforated partition wall 34 Behind it is the perforated partition wall 34.
  • the perforations are realized by two concentric rows of holes, the holes being circular. It is to be understood that the openings can also have a different shape. The ratio of the opening areas to the total area can also be different than shown.
  • the perforated partition wall 34 serves to reduce the flow velocity of the swirled air/fuel mixture from the area 36 of the Swirl body 30.
  • the partition 34 is limited by the wall of the swirl body 30.
  • the support gas nozzles 16b located behind them can be seen through the openings.
  • the second fuel nozzles 18 with their bores 62 are arranged at regular intervals on a circle around the central axis of the swirl body 30 .
  • the annular delta disc 66 which closes off the burner tube 12 .
  • the guide devices 68 extend inward in the radial direction.
  • three baffles 68 are provided.
  • the three guide devices 68 are evenly distributed over the inner circumference.
  • the combustion head 10b can also have more or fewer guide devices 68, which can then likewise be distributed uniformly over the inner circumference.
  • the guide devices 68 are triangular in shape and have a tip pointing inwards in the radial direction. The triangles point away from the annular delta disc 66 with an apex. How out figure 5 seen, the guide devices 68 are not in the plane of the 6 , but point away from the swirl body 30 . They are angled.
  • the guide devices 68 with the delta disc 66 are designed in such a way that they cause the formation of a vacuum zone which draws in exhaust gases from the combustion chamber. Delta disk 66 and guide devices 68 thus lead to an internal exhaust gas recirculation.
  • the shape in the manner of an angled triangle pointing away from the swirler leads to "standing vortices" on the guide devices 68, which contribute to the stabilization of the main flame front 26. Consequently, the recirculated exhaust gases are injected into the hot zones of the main flame and thus into the areas of greatest NO production.
  • the geometry of the guide devices 68 has been optimized in such a way that as high an internal exhaust gas quantity as possible is drawn into the main flame 26 . Both the number and the geometry of the guiding devices 68 must be taken into account both for the effect of the NO reduction and for the stability of the main flame.
  • the annular delta disc 66 can have a multiplicity of bulges 72 on its inner circumference between the guide devices 68 .
  • the bulges 72 form an interlocking geometry.
  • Semi-circular lobes are shown, but the teeth can be formed with other geometries.
  • the serration 72 is designed to create a larger surface area. The larger surface area results in a larger contact area between exhaust gas, combustion air and main fuel, a more intensive and uniform mixture of the fuel-air-exhaust gas mixture is produced. As a result, a more uniform distribution of combustion zones enriched with exhaust gas and thus stoichiometrically more favorable can form in the main flame 26 . The inventors have found that this further reduces the overall formation of thermal NO.
  • the second fuel nozzles 18 are shaped in such a way that the highest possible exit velocities are achieved.
  • an aperture can be provided in front of the axial opening of the fuel nozzle. Due to the high momentum of the outflowing gas, the intensity of the mixture of internally recirculated exhaust gas and fuel can be further advanced. A further optimization takes place through the position of the second fuel nozzles 18 in coordination with the geometry of the guide devices 68. The second fuel nozzles 18 are evenly distributed between the guide devices 68.
  • the advantageous low-nitrogen combustion is achieved by first introducing combustion air 28 into the burner tube 12 with an open end downstream. A part of the combustion air 28 is twisted in the twisting device 14 arranged in the burner tube 12 . A first quantity of fuel is fed directly into the swirl body 30 and mixed there with the swirled combustion air 28 . A primary flame is formed in the swirled fuel/combustion air mixture within the swirler. A second quantity of fuel is supplied downstream of the swirl device 14 . A main flame front is formed which stabilizes downstream of the combustor tube and spaced from the combustor tube. In this case, the first quantity of fuel is regulated independently of the second quantity of fuel.
  • the separate fuel control makes it possible to achieve very low NO emissions over a wide load range.
  • a different ratio of the first quantity of fuel to the second quantity of fuel can be optimal than at a high load. If the ratio of the two fuel quantities to one another is fixed, low NO emissions cannot be guaranteed over the entire load range of the burner.
  • less primary gas/support gas can be supplied as a percentage of the main gas than at high load.
  • the first amount of fuel decreases to a lesser extent than the amount of air through the swirler at lower loads, due to flow technology flows, so NO emissions can increase at lower loads even with a lean primary flame.
EP21182423.0A 2020-07-10 2021-06-29 Procédé de combustion étagée d'un combustible et tête de combustion Pending EP3940293A1 (fr)

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DE102020118325.9A DE102020118325A1 (de) 2020-07-10 2020-07-10 Verfahren zur gestuften verbrennung eines brennstoffes und brennkopf

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EP3940293A1 true EP3940293A1 (fr) 2022-01-19

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CN (1) CN113915613A (fr)
DE (1) DE102020118325A1 (fr)
EA (1) EA202191607A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4235027A1 (fr) * 2022-02-28 2023-08-30 Sofinter S.p.A. Installation de brûleur pour une chaudière et procédé de fonctionnement de l'installation de brûleur

Citations (7)

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Publication number Priority date Publication date Assignee Title
US4737100A (en) * 1986-04-30 1988-04-12 John Zink Company Duct burner apparatus
EP0612959A1 (fr) * 1993-02-23 1994-08-31 D.W. Clysan B.V. Brûleur à venturi
DE4427104A1 (de) * 1994-07-30 1996-02-01 Prematechnik Ges Fuer Verfahre Gasbrenner mit geringem Anteil von NOX-Gasen bei der Verbrennung von Brenngasen oder Brenngasgemischen
DE19509219A1 (de) 1995-03-17 1996-09-19 Ulrich Dreizler Verfahren zum Verbrennen von Brenngas
EP1754937A2 (fr) 2005-08-16 2007-02-21 E.C.B. GmbH Tête de brûleur et procédé pour brûler du combustible
EP2037173A1 (fr) 2007-09-14 2009-03-18 E.C.B. GmbH Tête de brûleur et procédé de combustion à un étage de combustible dans une zone de combustion éloignée de la tête de brûleur
EP3078910A1 (fr) * 2015-04-08 2016-10-12 Vysoké Ucení Technické V Brne Brûleur à gaz a combustion étagée

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7878798B2 (en) 2006-06-14 2011-02-01 John Zink Company, Llc Coanda gas burner apparatus and methods
CN111051776B (zh) 2017-09-05 2022-08-02 约翰·尊科股份有限公司 低nox和co燃烧器方法及设备

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4737100A (en) * 1986-04-30 1988-04-12 John Zink Company Duct burner apparatus
EP0612959A1 (fr) * 1993-02-23 1994-08-31 D.W. Clysan B.V. Brûleur à venturi
DE4427104A1 (de) * 1994-07-30 1996-02-01 Prematechnik Ges Fuer Verfahre Gasbrenner mit geringem Anteil von NOX-Gasen bei der Verbrennung von Brenngasen oder Brenngasgemischen
DE19509219A1 (de) 1995-03-17 1996-09-19 Ulrich Dreizler Verfahren zum Verbrennen von Brenngas
EP1754937A2 (fr) 2005-08-16 2007-02-21 E.C.B. GmbH Tête de brûleur et procédé pour brûler du combustible
EP2037173A1 (fr) 2007-09-14 2009-03-18 E.C.B. GmbH Tête de brûleur et procédé de combustion à un étage de combustible dans une zone de combustion éloignée de la tête de brûleur
EP3078910A1 (fr) * 2015-04-08 2016-10-12 Vysoké Ucení Technické V Brne Brûleur à gaz a combustion étagée

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4235027A1 (fr) * 2022-02-28 2023-08-30 Sofinter S.p.A. Installation de brûleur pour une chaudière et procédé de fonctionnement de l'installation de brûleur

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EA202191607A1 (ru) 2022-01-31
DE102020118325A1 (de) 2022-01-13

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