EP0984223B1 - Combustion process for burning a fuel - Google Patents

Combustion process for burning a fuel Download PDF

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Publication number
EP0984223B1
EP0984223B1 EP99402117A EP99402117A EP0984223B1 EP 0984223 B1 EP0984223 B1 EP 0984223B1 EP 99402117 A EP99402117 A EP 99402117A EP 99402117 A EP99402117 A EP 99402117A EP 0984223 B1 EP0984223 B1 EP 0984223B1
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Prior art keywords
jet
fuel
oxidizer
main
injected
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EP99402117A
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German (de)
French (fr)
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EP0984223A1 (en
Inventor
Jacques Dugue
Jean-Michel Samaniego
Bernard Labegorre
Olivier Charon
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LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA a Directoire et Conseil de Surveillance pour lEtude et lExploitation des Procedes Georges Claude
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Application filed by Air Liquide SA, LAir Liquide SA a Directoire et Conseil de Surveillance pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C7/00—Combustion apparatus characterised by arrangements for air 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 
    • 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
    • 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
    • F23D17/00—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel
    • F23D17/002—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel gaseous or liquid fuel

Definitions

  • the invention relates to a method for burning a fuel in which is injected into a combustion zone at least one jet of fuel and, at a distance therefrom, at least one main jet of an oxidant.
  • the document EP 754 912 proposes a combustion process in which the fuel and oxidant jets are distributed geometrically from so as to give the fuel and oxidant flows angles and speeds leading to a stable and luminous flame.
  • the invention aims to overcome these drawbacks by proposing a method combustion to obtain stable combustion, low emission nitrogen oxides, despite a distance between the oxidant jets and fuel far superior to that described in the prior art such as USP 4988285.
  • the subject of the invention is a combustion method for burning a fuel, in which at least one jet of fuel is injected simultaneously into a main combustion zone and at a distance from it at least one main jet of an oxidant, in which the injection point of each main oxidant jet is placed relative to the injection point of the fuel jet closest to it at a distance D satisfying at least one of the following relationships: D AT > 5 (and preferably> 10) and / or D B > 5 (and preferably> 10) D being defined as the minimum distance between the outer edge of the oxidant jet considered and the outer edge of the fuel jet closest to it, at their respective injection points, and A and B being respectively the section of the main jet of the oxidant and the section of the fuel jet, the sections being considered at the point of injection of the jets, so as to keep the main oxidant and fuel jets separate until said at least one main jet d oxidant and / or the fuel jet has caused an amount of a substantially inert surrounding fluid.
  • the amount of surrounding fluid ent ent
  • the invention is characterized in that one injects into an auxiliary combustion zone located upstream of said main combustion zone at least one auxiliary jet of an oxidant to stabilize combustion in said main combustion zone, the point d injection of said auxiliary oxidant jet being disposed at a distance D s from the associated fuel jet, D s satisfying the following relationship: D s AT s ⁇ 5 D s being the minimum distance between the external edge of the auxiliary oxidant jet considered and the external edge of the associated fuel jet, at their respective injection points, and A s being the section of the auxiliary oxidant jet considered at its injection point, so as to obtain a substantially uniform combustion.
  • a distance D verifying at least one of the two preceding relationships allows the main oxidant jet and the fuel jet to entrain a quantity of surrounding fluid, notably substantially inert, before they react. with the other.
  • each of the relationships implies that the total flow contained in the jet is at least 1.8 times the initial flow of the entraining jet.
  • the ratio (jet flow / initial flow) increases when the ratio (entraining fluid density / entrained fluid density) decreases.
  • each of the two inequalities makes it possible to obtain a dilution of each of the jets of main oxidant and of fuel.
  • the implementation of this invention will be done with a distance D satisfying at least one of the above relationships, and preferably satisfying D / A 0.5 > 10 and / or D / B 0.5 > 10, so that the flow of one of the jets at least and preferably of each jet (initial flow plus surrounding fluid substantially inert) or at least 3.6 times the initial flow of the entraining jet.
  • the method is characterized in that the total flow of oxidant injected by said jets is regulated main and auxiliary oxidant at a value higher than the flow rate stoichiometric oxidant necessary to burn all the fuel injected in the combustion zone by said at least one fuel jet.
  • the flow rate of the oxidant injected by said at least is regulated an auxiliary jet at a value less than 30%, preferably between 2% and 15% of the total oxidant flow injected into the combustion zone.
  • substantially uniform combustion means that obtains a substantially uniform combustion zone characterized by a volume of combustion zone at least doubled compared to a flame where fuel and oxidant jets mix quickly without dilution with combustion products, and a temperature field with small gradients in the flame volume, such as for an oxidant composed of pure oxygen, the maximum average temperature is at least lower minus 500 ° C at the theoretical adiabatic temperature of the mixture fuel / oxidant.
  • the total momentum (fuel + oxidizer) of the jets of fluid related to a unit of power will preferably be greater than approximately 3 N / MW, of so as to obtain a satisfactory mixture of gases (the momentum -or "momentum" - is defined here as the product of a mass flow (kg / s) by a speed (m / s)).
  • Case 1 corresponds to very low injection speeds for oxidant and weak for natural gas. Practice shows that flames produced are sensitive to buoyancy forces and can create points hot on the roof of an oven, due to the raising of the rear part of the flame. Cases 2 to 5 show different examples where the mixture of gases is provided by a momentum provided either by the oxidant jets, either by the fuel jets, or by both.
  • substantially inert surrounding fluid means the fluid (usually a gas) located near the main oxidant jet. In general, it consists of the combustion gases which recirculate throughout the area of combustion as well as in the vicinity of injections of oxidizing fluids and combustible, these combustion gases being more or less diluted by the air present in this combustion zone, air of which only the species generally remain inert (nitrogen, argon) that have not reacted with the fuel.
  • Figures 1 and 2 illustrate a first embodiment of a combustion installation for implementing the method according to the invention.
  • the installation 1 comprises, for initiate or maintain combustion in a main area of combustion 2, on the one hand an injector 3 of a central fuel jet 4 (shown in dashed lines), such as a jet of natural gas, and on the other hand two identical injectors 5 and 6 of main jets of an oxidant 7 and 8 (shown in solid lines), for example air, possibly enriched with oxygen, or pure oxygen, arranged diametrically opposite by compared to the injector 3 of the central fuel jet 4.
  • a central fuel jet 4 shown in dashed lines
  • an oxidant 7 and 8 shown in solid lines
  • the injector 3 is connected to a fuel supply 9, and the injectors 5 and 6, to a supply oxidant 10.
  • this further comprises an injector 13 of an auxiliary jet oxidant 14 (shown in phantom) in an auxiliary zone 2A of combustion (represented by hatching) located upstream of the area main combustion 2.
  • the auxiliary jet 14 is arranged near the injector 3 of the central fuel jet 4 and associated with it.
  • the injector 13 is also supplied by the power supply oxidant 10.
  • the oxidant supply 10 comprises, connected to the oxidant injectors 5, 6 and 13, means 15 for distributing the total flow rate of oxidant injected into a first fraction feeding the injectors 5 and 6 of the main jets 7 and 8 of oxidant and a second fraction, complementary to the first, feeding the injector 13 of the auxiliary oxidant jet 14.
  • These distribution means 15 can for example be produced by a pipe pricking in diversion on a main line supply of oxidant from supply 10 and in which is disposed a valve to regulate the fraction of the total flow rate of the oxidant supplying the auxiliary injector 13.
  • the various injectors 3, 5, 6 and 13 have for example circular outlet openings so as to form conical jets widening in their directions of projection respective indicated by arrows 20, 22, 24, and 26 in Figure 1. But we may also provide other forms of outlet orifices such as for example orifices in the form of a slot, ellipse, ring or the like to modify the shape jets.
  • the two main jets 7 and 8 of oxidant injected in the main combustion zone 2 simultaneously the central jet 4 of fuel and away from it as well as diametrically opposed by compared to him, the two main jets 7 and 8 of oxidant.
  • the central fuel jet 4 is preferably injected with a speed below 75m / s while the two main jets 7 and 8 of oxidant are injected at a speed preferably between 50 and 150m / s.
  • D represents the minimum distance between the outer edge of the oxidant jet considered, 7 or 8, and the outer edge of the fuel 4 at their respective injection points (see Figure 2), and A represents the section of the main jet of the oxidant considered 7 or 8 at its point injection.
  • the jets of oxidant 7 and 8 and of fuel 4 do not begin to mix only from a distance L from the injection points respective, in mixing zones 30, 31 shown in gray.
  • the separation of the jets over this distance L allows them, in particular to the jets 7 and 8 main oxidant, cause a significant amount of fluid surrounding substantially inert, as shown by arrows 32 in Figure 1.
  • This entrained amount of the surrounding fluid is generally more than five, preferably ten times the jet flow causing this fluid.
  • this surrounding fluid is mainly composed of combustion products.
  • the oxidant / fuel mixture in mixing zones 30 and 31, increases the volume occupied by the main combustion zone 2. This has for effect of homogenizing the spatial distribution of the temperature field in this main combustion zone 2 and decrease the average temperature in it, so that the emission of nitrogen oxides is efficiently scaled down.
  • the distance D also satisfies the following relationship: D AT vs > 5 where A c represents the section of the fuel jet at its injection point.
  • the auxiliary oxidant jet 14 is also injected into the main combustion zone 2, at a distance D s from the associated jet 4 of fuel. Stabilization of the combustion in the main zone 2 is provided by the presence of the auxiliary combustion zone 2A upstream, which thus ensures a region of stable ignition of the oxidant / fuel mixture in the zone 2.
  • D s satisfies the following relationship: D s AT s ⁇ 5
  • D s represents the minimum distance between the external edge of the auxiliary oxidant jet 14 considered and the external edge of the associated fuel jet 4, at their respective injection points, and A s represents the section of the auxiliary oxidant jet 14 at its injection point.
  • the sections A, A c , and A s of the jets at their respective injection points are determined by taking into account their particular geometric shapes.
  • the distances D minimum between the outer edges of the respective oxidant and fuel can also be different, namely a jet of oxidant having a smaller section can be arranged closer to the fuel jet than the one with a larger section.
  • jet injectors can be provided. fuel and several main oxidant jet injectors. In that case, to satisfy relation (I), consider for each main throw oxidizing the closest jet of fuel to it.
  • Figure 4 shows in a front view identical to that of the Figure 2 another variant of an installation 1 for the implementation of process according to the invention.
  • the installation of this variant comprises three injectors 50, 51 and 52 of three jets of a first fuel, for example natural gas, which are coplanar with injectors 55 and 56 of main oxidant jets arranged diametrically opposite with respect to the injectors 50, 51 and 52, and an injector 53 of a jet of a second fuel, for example fuel oil, disposed above of the three injectors 50, 51 and 52 of the jets of the first fuel and allowing to alternate the fuel used.
  • a first fuel for example natural gas
  • injectors 55 and 56 of main oxidant jets arranged diametrically opposite with respect to the injectors 50, 51 and 52
  • an injector 53 of a jet of a second fuel for example fuel oil
  • the injectors 55 and 56 and therefore the jets main oxidant sprayed into the combustion zone by them find, at their respective injection points, at a minimum distance D between the outer edges with respect to the nearest fuel jet, i.e. the jet projected by the injector 50 with respect to the main injector 55 and the injector 52 with respect to the main injector 56, so as to respect relations (I) and (II).
  • auxiliary injectors 57 and 58 of auxiliary oxidant jets are disposed above the three injectors 50, 51 and 52 of the fuel jets, one of which 57 is associated with the injectors 50, 51 and 53 and the other of which 58 is associated with the injectors 51, 52 and 53.
  • These auxiliary injectors 57 and 58 are located at a minimum distance D s between the external edges of the fuel jets so as to respect the relationship (III).
  • FIG. 5 shows by way of indication a graph representing a result obtained with the method according to the invention implemented using an installation of the type shown in FIGS. 1 and 2 and in which the distance D defined could be adjusted higher of the main oxidant jets relative to the central fuel jet.
  • This graph shows the quantity of nitrogen oxides (NO x ) produced during combustion as a function of the parameter D / ⁇ A defined above.

Abstract

The combustion procedure, in which fuel and oxidant are injected simultaneously into the combustion zone, has the injection point of each main oxidant jet situated at a distance (D) from the injection point of the nearest fuel jet which is at least five times and preferably 10 times the square root of the oxidant or fuel jet sections. The distance (D) is determined as the distance between the outer edges of a fuel jet (3) and an oxidant jet (5, 6).

Description

L'invention est relative à un procédé pour brûler un combustible dans lequel on injecte dans une zone de combustion au moins un jet de combustible et, à distance de celui-ci, au moins un jet principal d'un oxydant.The invention relates to a method for burning a fuel in which is injected into a combustion zone at least one jet of fuel and, at a distance therefrom, at least one main jet of an oxidant.

Il est connu de USP 4,988,285 un procédé de combustion permettant de réduire la formation d'oxydes d'azote du type Nox, dans lequel on injecte dans une zone de combustion un jet de combustible, par exemple du gaz naturel, et un jet principal d'un oxydant, par exemple de l'air ou de l'air enrichi en oxygène, disposé à une faible distance du jet de combustible, de préférence comprise entre 4 à 20 fois le diamètre du jet d'oxydant principal.It is known from USP 4,988,285 a combustion process allowing to reduce the formation of nitrogen oxides of the Nox type, into which one injects in a combustion zone a jet of fuel, for example gas natural, and a main jet of an oxidant, for example air or air enriched in oxygen, placed a short distance from the fuel jet, preferably between 4 to 20 times the diameter of the main oxidant jet.

La Demanderesse a cependant constaté qu'un tel procédé de combustion connu conduit à la production d'une quantité trop importante d'oxydes d'azote lorsque les jets de combustible et d'oxydant principal sont disposés à faible distance l'un de l'autre.The Applicant has however noted that such a method of known combustion leads to the production of too large a quantity nitrogen oxides when the fuel and main oxidant jets are arranged at a short distance from each other.

Lorsqu'on éloigne l'un de l'autre les jets d'oxydant et de combustible pour réduire l'émission des oxydes d'azote, on se trouve alors confronté à des problèmes de stabilité de la combustion entretenue (la flamme peut s'éteindre par instants) et à la présence de combustible imbrûlé dans les fumées de ce qui est également nocif pour l'environnement.When the oxidant and fuel jets are moved away from each other to reduce the emission of nitrogen oxides, we are then confronted with problems with the stability of the sustained combustion (the flame can extinguish at times) and the presence of unburnt fuel in the fumes from which is also harmful to the environment.

Le document US 4,541,796 propose un procédé de combustion dans lequel l'oxydant est injecté sous forme de plusieurs jets. Ces jets d'oxydant sont situés à une distance X du jet de combustible qui leur est le plus proche, la distance X étant supérieure à au moins 8 fois le diamètre D du jet d'oxydant.Document US 4,541,796 proposes a combustion process in which the oxidant is injected in the form of several jets. These oxidant jets are located at a distance X from the most fuel jet close, the distance X being greater than at least 8 times the diameter D of the jet oxidant.

Le document EP 754 912 propose un procédé de combustion dans lequel les jets de combustible et d'oxydant sont répartis géométriquement de manière à donner aux flux de combustible et d'oxydant des angles et des vitesses conduisant à une flamme stable et lumineuse.The document EP 754 912 proposes a combustion process in which the fuel and oxidant jets are distributed geometrically from so as to give the fuel and oxidant flows angles and speeds leading to a stable and luminous flame.

L'invention vise à pallier ces inconvénients en proposant un procédé de combustion permettant d'obtenir une combustion stable, à faible émission d'oxydes d'azote, malgré une distance entre les jets d'oxydant et de combustible bien supérieure à celle décrite dans l'art antérieur tel que USP 4,988,285. The invention aims to overcome these drawbacks by proposing a method combustion to obtain stable combustion, low emission nitrogen oxides, despite a distance between the oxidant jets and fuel far superior to that described in the prior art such as USP 4988285.

A cet effet, l'invention a pour objet un procédé de combustion pour brûler un combustible, dans lequel on injecte simultanément dans une zone principale de combustion au moins un jet de combustible et à distance de celui-ci au moins un jet principal d'un oxydant, dans lequel on dispose le point d'injection de chaque jet principal d'oxydant par rapport au point d'injection du jet de combustible le plus proche de lui à une distance D satisfaisant l'une au moins des relations suivantes : D A > 5 (et de préférence > 10) et/ou D B > 5 (et de préférence > 10) D étant définie comme la distance minimale entre le bord externe du jet d'oxydant considéré et le bord externe du jet de combustible le plus proche de lui, à leurs points respectifs d'injection, et A et B étant respectivement la section du jet principal de l'oxydant et la section du jet de combustible, les sections étant considérées au point d'injection des jets, de manière à maintenir les jets principal d'oxydant et de combustible séparés jusqu'à ce que ledit au moins un jet principal d'oxydant et/ou le jet de combustible ait entraíné une quantité d'un fluide environnant sensiblement inerte. De préférence, la quantité de fluide environnant entraíné est supérieure à cinq, encore plus préférentiellement à dix fois son propre débitTo this end, the subject of the invention is a combustion method for burning a fuel, in which at least one jet of fuel is injected simultaneously into a main combustion zone and at a distance from it at least one main jet of an oxidant, in which the injection point of each main oxidant jet is placed relative to the injection point of the fuel jet closest to it at a distance D satisfying at least one of the following relationships: D AT > 5 (and preferably> 10) and / or D B > 5 (and preferably> 10) D being defined as the minimum distance between the outer edge of the oxidant jet considered and the outer edge of the fuel jet closest to it, at their respective injection points, and A and B being respectively the section of the main jet of the oxidant and the section of the fuel jet, the sections being considered at the point of injection of the jets, so as to keep the main oxidant and fuel jets separate until said at least one main jet d oxidant and / or the fuel jet has caused an amount of a substantially inert surrounding fluid. Preferably, the amount of surrounding fluid entrained is greater than five, even more preferably ten times its own flow

L'invention est caractérisée en ce que l'on injecte dans une zone auxiliaire de combustion située en amont de ladite zone principale de combustion au moins un jet auxiliaire d'un oxydant pour stabiliser la combustion dans ladite zone principale de combustion, le point d'injection dudit jet auxiliaire d'oxydant étant disposé à une distance Ds du jet associé de combustible, Ds satisfaisant à la relation suivante : Ds As <5 Ds étant la distance minimale entre le bord externe du jet auxiliaire d'oxydant considéré et le bord externe du jet associé de combustible, à leurs points respectifs d'injection, et As étant la section du jet auxiliaire d'oxydant considéré à son point d'injection, de manière à obtenir une combustion sensiblement uniforme. The invention is characterized in that one injects into an auxiliary combustion zone located upstream of said main combustion zone at least one auxiliary jet of an oxidant to stabilize combustion in said main combustion zone, the point d injection of said auxiliary oxidant jet being disposed at a distance D s from the associated fuel jet, D s satisfying the following relationship: D s AT s <5 D s being the minimum distance between the external edge of the auxiliary oxidant jet considered and the external edge of the associated fuel jet, at their respective injection points, and A s being the section of the auxiliary oxidant jet considered at its injection point, so as to obtain a substantially uniform combustion.

L'utilisation d'une distance D vérifiant au moins l'une des deux relations précédentes permet au jet principal d'oxydant et au jet de combustible d'entraíner une quantité de fluide environnant notamment sensiblement inerte avant qu'ils ne réagissent l'un avec l'autre. En prenant comme référence comme commencement de leur interaction (et au début de la zone de combustion principale) le point de rencontre des bords du jet d'oxydant principal et du jet de combustible, pour des jets sensiblement parallèles, chacune des relations implique que le débit total contenu dans le jet est au moins 1.8 fois le débit initial du jet entraínant. Le rapport (débit jet/débit initial) augmente lorsque le rapport (masse volumique fluide entraínant/masse volumique fluide entraíné) diminue. La vérification de chacune des deux inégalités permet d'obtenir une dilution de chacun des jets d'oxydant principal et de combustible. La mise en oeuvre de cette invention se fera avec une distance D satisfaisant au moins l'une des relations ci-dessus, et de préférence satisfaisant D/A0.5 > 10 et/ou D/B0.5 > 10, de façon à ce que le débit de l'un des jets au moins et de préférence de chaque jet (débit initial plus fluide environnant sensiblement inerte) soit au moins 3.6 fois le débit initial du jet entraínant.The use of a distance D verifying at least one of the two preceding relationships allows the main oxidant jet and the fuel jet to entrain a quantity of surrounding fluid, notably substantially inert, before they react. with the other. Taking as reference as the beginning of their interaction (and at the beginning of the main combustion zone) the meeting point of the edges of the main oxidant jet and the fuel jet, for substantially parallel jets, each of the relationships implies that the total flow contained in the jet is at least 1.8 times the initial flow of the entraining jet. The ratio (jet flow / initial flow) increases when the ratio (entraining fluid density / entrained fluid density) decreases. The verification of each of the two inequalities makes it possible to obtain a dilution of each of the jets of main oxidant and of fuel. The implementation of this invention will be done with a distance D satisfying at least one of the above relationships, and preferably satisfying D / A 0.5 > 10 and / or D / B 0.5 > 10, so that the flow of one of the jets at least and preferably of each jet (initial flow plus surrounding fluid substantially inert) or at least 3.6 times the initial flow of the entraining jet.

Selon un mode préférentiel de réalisation, le procédé est caractérisé en ce que l'on régule le débit total d'oxydant injecté par lesdits jets principal et auxiliaire d'oxydant à une valeur supérieure au débit stoechiométrique d'oxydant nécessaire pour brûler tout le combustible injecté dans la zone de combustion par ledit au moins un jet de combustible. De préférence également, on régule le débit de l'oxydant injecté par ledit au moins un jet auxiliaire à une valeur inférieure à 30%, de préférence compris entre 2% et 15% du débit total d'oxydant injecté dans la zone de combustion.According to a preferred embodiment, the method is characterized in that the total flow of oxidant injected by said jets is regulated main and auxiliary oxidant at a value higher than the flow rate stoichiometric oxidant necessary to burn all the fuel injected in the combustion zone by said at least one fuel jet. Of preferably also, the flow rate of the oxidant injected by said at least is regulated an auxiliary jet at a value less than 30%, preferably between 2% and 15% of the total oxidant flow injected into the combustion zone.

Le procédé selon l'invention peut de plus comporter une ou plusieurs des caractéristiques suivantes :

  • on injecte symétriquement autour dudit au moins un jet de combustible, plusieurs jets principaux d'oxydant,
  • on injecte dans ladite zone de combustion deux jets principaux d'oxydant disposés diamétralement opposés par rapport à au moins un jet central de combustible,
  • on injecte dans ladite zone de combustion trois jets centraux de combustible, coplanaires avec les deux jets principaux d'oxydant disposés diamétralement opposés par rapport aux trois jets centraux de combustible,
  • on injecte dans ladite zone de combustion au moins un jet d'un premier combustible, notamment du gaz naturel, et au moins un jet d'un second combustible, notamment du fioul (le combustible peut être dans tous les cas, solide, liquide et/ou gazeux).
The method according to the invention can also include one or more of the following characteristics:
  • several principal oxidant jets are injected symmetrically around said at least one jet of fuel,
  • two main jets of oxidant are placed in said combustion zone arranged diametrically opposite with respect to at least one central jet of fuel,
  • three central fuel jets, coplanar with the two main oxidant jets arranged diametrically opposite with respect to the three central fuel jets, are injected into said combustion zone,
  • injecting into said combustion zone at least one jet of a first fuel, in particular natural gas, and at least one jet of a second fuel, in particular fuel oil (the fuel can in any case be solid, liquid and / or gaseous).

Le terme "combustion sensiblement uniforme" signifie que l'on obtient une zone de combustion sensiblement uniforme caractérisée par un volume de zone de combustion au moins doublé par rapport à une flamme où les jets de combustible et d'oxydant se mélangent rapidement sans dilution préalable avec des produits de combustion, et un champ de température avec de faibles gradients dans le volume de la flamme, tel que, pour un oxydant composé d'oxygène pur, la température moyenne maximale est inférieure d'au moins 500°C à la température adiabatique théorique du mélange combustible/oxydant.The term "substantially uniform combustion" means that obtains a substantially uniform combustion zone characterized by a volume of combustion zone at least doubled compared to a flame where fuel and oxidant jets mix quickly without dilution with combustion products, and a temperature field with small gradients in the flame volume, such as for an oxidant composed of pure oxygen, the maximum average temperature is at least lower minus 500 ° C at the theoretical adiabatic temperature of the mixture fuel / oxidant.

La quantité de mouvement totale (combustible + comburant) des jets de fluide rapportée à une unité de puissance (et qui sera donc exprimée en Newton/Megawatt) sera de préférence supérieure à environ 3 N/MW, de manière à obtenir un mélange satisfaisant des gaz (la quantité de mouvement -ou "momentum"- est ici définie comme le produit d'un débit massique (kg/s) par une vitesse (m/s)). The total momentum (fuel + oxidizer) of the jets of fluid related to a unit of power (and which will therefore be expressed in Newton / Megawatt) will preferably be greater than approximately 3 N / MW, of so as to obtain a satisfactory mixture of gases (the momentum -or "momentum" - is defined here as the product of a mass flow (kg / s) by a speed (m / s)).

Le tableau ci-après (ramené à une puissance de brûleur de 1 MW) résume les différents résultats obtenus par une flamme oxygène/gaz naturel (de 1 MW) : OXYGENE NATURAL GAS TOTAL Cas Vitesse Quantité de mouvement (N) Vitesse (m/s) Quantité de mouvement (N) Quantité de mouvement (N) 1 10 0.9 50 1.1 2.0 2 10 0.9 100 2.2 3.1 3 60 5.1 5 0.1 5.2 4 100 8.5 100 2.2 10.7 5 300 25.5 400 8.8 34.3 The table below (reduced to a burner power of 1 MW) summarizes the different results obtained by an oxygen / natural gas flame (of 1 MW): OXYGEN NATURAL GAS TOTAL Case Speed Movement amount (N) Speed (m / s) Movement amount (N) Movement amount (N) 1 10 0.9 50 1.1 2.0 2 10 0.9 100 2.2 3.1 3 60 5.1 5 0.1 5.2 4 100 8.5 100 2.2 10.7 5 300 25.5 400 8.8 34.3

Le cas 1 correspond à des vitesses d'injection très faibles pour l'oxydant et faible pour le gaz naturel. La pratique montre que les flammes produites sont sensibles aux forces de flottabilités et peuvent créer des points chauds sur la voûte d'un four, du fait du relèvement de la partie arrière de la flamme. Les cas 2 à 5 montrent différents exemples où le mélange des gaz est assuré par une quantité de mouvement apportée soit par les jets d'oxydant, soit par les jets de combustible, soit par les deux.Case 1 corresponds to very low injection speeds for oxidant and weak for natural gas. Practice shows that flames produced are sensitive to buoyancy forces and can create points hot on the roof of an oven, due to the raising of the rear part of the flame. Cases 2 to 5 show different examples where the mixture of gases is provided by a momentum provided either by the oxidant jets, either by the fuel jets, or by both.

Le terme fluide environnant sensiblement inerte signifie le fluide (en général un gaz) situé à proximité du jet d'oxydant principal. En général, il est constitué par les gaz de combustion qui recirculent dans toute la zone de combustion ainsi qu'au voisinage des injections de fluides comburant et combustible, ces gaz de combustion étant plus ou moins dilué par l'air présent dans cette zone de combustion, air dont il ne reste en général que les espèces inertes (azote, argon) qui n'ont pas réagi avec le combustible.The term substantially inert surrounding fluid means the fluid (usually a gas) located near the main oxidant jet. In general, it consists of the combustion gases which recirculate throughout the area of combustion as well as in the vicinity of injections of oxidizing fluids and combustible, these combustion gases being more or less diluted by the air present in this combustion zone, air of which only the species generally remain inert (nitrogen, argon) that have not reacted with the fuel.

D'autres caractéristiques et avantages de l'invention ressortiront de la description suivante, donnée à titre d'exemple, sans caractère limitatif, en regard des dessins annexés sur lesquels :

  • La figure 1 est un schéma d'une installation de combustion pour la mise en oeuvre du procédé de combustion selon l'invention,
  • La figure 2 est un schéma en vue de face de l'installation de la figure 1,
  • La figure 3 est un schéma selon une vue identique à celle de la figure 2 d'une première variante d'une installation de combustion pour illustrer un développement du procédé selon l'invention,
  • La figure 4 est un schéma selon une vue identique à celle de la figure 2 d'une seconde variante d'une installation de combustion pour illustrer un autre développement du procédé selon l'invention, et
  • La figure 5 est un graphique montrant l'émission en oxydes d'azote d'une installation mettant en oeuvre le procédé selon l'invention.
    • Other characteristics and advantages of the invention will emerge from the following description, given by way of example, without limitation, with reference to the appended drawings in which:
  • FIG. 1 is a diagram of a combustion installation for implementing the combustion method according to the invention,
  • FIG. 2 is a diagram in front view of the installation of FIG. 1,
  • FIG. 3 is a diagram according to a view identical to that of FIG. 2 of a first variant of a combustion installation to illustrate a development of the method according to the invention,
  • FIG. 4 is a diagram according to a view identical to that of FIG. 2 of a second variant of a combustion installation to illustrate another development of the method according to the invention, and
  • FIG. 5 is a graph showing the emission of nitrogen oxides from an installation implementing the method according to the invention.

    • Les figures 1 et 2 illustrent un premier exemple de réalisation d'une installation de combustion pour la mise en oeuvre du procédé selon l'invention.Figures 1 and 2 illustrate a first embodiment of a combustion installation for implementing the method according to the invention.

    En référence à ces figures 1 et 2, l'installation 1 comprend, pour amorcer ou entretenir une combustion dans une zone principale de combustion 2, d'une part un injecteur 3 d'un jet central de combustible 4 (représenté en traits interrompus), comme par exemple un jet de gaz naturel, et d'autre part deux injecteurs identiques 5 et 6 de jets principaux d'un oxydant 7 et 8 (représentés en traits pleins), par exemple de l'air, éventuellement enrichi d'oxygène, ou de l'oxygène pur, disposés diamétralement opposés par rapport à l'injecteur 3 du jet central de combustible 4. With reference to these Figures 1 and 2, the installation 1 comprises, for initiate or maintain combustion in a main area of combustion 2, on the one hand an injector 3 of a central fuel jet 4 (shown in dashed lines), such as a jet of natural gas, and on the other hand two identical injectors 5 and 6 of main jets of an oxidant 7 and 8 (shown in solid lines), for example air, possibly enriched with oxygen, or pure oxygen, arranged diametrically opposite by compared to the injector 3 of the central fuel jet 4.

    Pour leur approvisionnement respectif, l'injecteur 3 est relié à une alimentation de combustible 9, et les injecteurs 5 et 6, à une alimentation d'oxydant 10.For their respective supply, the injector 3 is connected to a fuel supply 9, and the injectors 5 and 6, to a supply oxidant 10.

    Par ailleurs, pour stabiliser la flamme et/ou faciliter le démarrage de l'installation 1, celle-ci comprend en outre un injecteur 13 d'un jet auxiliaire d'oxydant 14 (représenté en traits mixtes) dans une zone auxiliaire 2A de combustion (représentée par des haçhures) située en amont de la zone principale 2 de combustion. Comme on le voit sur la figure, le jet auxiliaire 14 est disposé à proximité de l'injecteur 3 du jet central de combustible 4 et associé à celui-ci. L'injecteur 13 est également approvisionné par l'alimentation d'oxydant 10.Furthermore, to stabilize the flame and / or facilitate starting of installation 1, this further comprises an injector 13 of an auxiliary jet oxidant 14 (shown in phantom) in an auxiliary zone 2A of combustion (represented by hatching) located upstream of the area main combustion 2. As can be seen in the figure, the auxiliary jet 14 is arranged near the injector 3 of the central fuel jet 4 and associated with it. The injector 13 is also supplied by the power supply oxidant 10.

    Afin de pouvoir maítriser aisément le débit total d'oxygène injecté par les jets principaux 7, 8 et auxiliaire 14 d'oxydant respectivement dans la zone 2 de combustion et dans la zone auxiliaire 2A de combustion, l'alimentation d'oxydant 10 comprend, reliés aux injecteurs d'oxydant 5, 6 et 13, des moyens 15 de répartition du débit total d'oxydant injecté en une première fraction alimentant les injecteurs 5 et 6 des jets 7 et 8 principaux d'oxydant et une seconde fraction, complémentaire à la première, alimentant l'injecteur 13 du jet auxiliaire d'oxydant 14.In order to easily control the total flow of oxygen injected by the main jets 7, 8 and auxiliary 14 of oxidant respectively in the combustion zone 2 and in the auxiliary combustion zone 2A, the oxidant supply 10 comprises, connected to the oxidant injectors 5, 6 and 13, means 15 for distributing the total flow rate of oxidant injected into a first fraction feeding the injectors 5 and 6 of the main jets 7 and 8 of oxidant and a second fraction, complementary to the first, feeding the injector 13 of the auxiliary oxidant jet 14.

    Ces moyens 15 de répartition peuvent par exemple être réalisés par une conduite se piquant en dérivation sur une ligne principale d'alimentation en oxydant de l'alimentation 10 et dans laquelle est disposée une vanne pour réguler la fraction du débit total de l'oxydant alimentant l'injecteur auxiliaire 13.These distribution means 15 can for example be produced by a pipe pricking in diversion on a main line supply of oxidant from supply 10 and in which is disposed a valve to regulate the fraction of the total flow rate of the oxidant supplying the auxiliary injector 13.

    Ainsi que l'on voit sur la figure 2, les divers injecteurs 3, 5, 6 et 13 possèdent par exemple des orifices de sortie circulaires de manière à former des jets coniques s'élargissant dans leurs directions de projection respectives indiquées par des flèches 20, 22, 24, et 26 sur la figure 1. Mais on peut aussi prévoir d'autre formes d'orifices de sortie comme par exemple des orifices en forme de fente, d'ellipse, d'anneau ou autre pour modifier la forme des jets.As seen in Figure 2, the various injectors 3, 5, 6 and 13 have for example circular outlet openings so as to form conical jets widening in their directions of projection respective indicated by arrows 20, 22, 24, and 26 in Figure 1. But we may also provide other forms of outlet orifices such as for example orifices in the form of a slot, ellipse, ring or the like to modify the shape jets.

    Lors de la mise en ouvre du procédé selon l'invention, on injecte dans la zone principale 2 de combustion simultanément le jet central 4 de combustible et, à distance de celui-ci ainsi que diamétralement opposés par rapport à lui, les deux jets 7 et 8 principaux d'oxydant. On régule le débit total d'oxydant injecté par les jets principaux 7 et 8 et auxiliaire d'oxydant 14 de façon à ce qu'il soit supérieur au débit stoechiométrique d'oxydant nécessaire pour brûler tout le combustible injecté dans la zone de combustion 2 afin de réaliser une combustion complète, c'est-à-dire une combustion ne produisant pratiquement pas de combustible imbrûlé.During the implementation of the method according to the invention, injected in the main combustion zone 2 simultaneously the central jet 4 of fuel and away from it as well as diametrically opposed by compared to him, the two main jets 7 and 8 of oxidant. We regulate the total flow oxidant injected by the main jets 7 and 8 and oxidant auxiliary 14 of so that it is greater than the stoichiometric flow rate of oxidant required to burn all the fuel injected into combustion zone 2 in order to achieve complete combustion, i.e. combustion which does not produce practically no unburnt fuel.

    Avantageusement, en régime stable de fonctionnement, on régule le débit d'oxydant injecté par le jet auxiliaire d'oxydant à une valeur inférieure à 30%, et de préférence à une valeur comprise entre 2 et 15% du débit total d'oxydant injecté dans la zone de combustion.Advantageously, in stable operating conditions, one regulates the oxidant flow injected by the auxiliary oxidant jet to a value less than 30%, and preferably at a value between 2 and 15% of the total flow of oxidant injected into the combustion zone.

    Le jet central 4 de combustible est de préférence injecté avec une vitesse inférieure à 75m/s tandis que les deux jets 7 et 8 principaux d'oxydant sont injectés à une vitesse comprise de préférence entre 50 et 150m/s.The central fuel jet 4 is preferably injected with a speed below 75m / s while the two main jets 7 and 8 of oxidant are injected at a speed preferably between 50 and 150m / s.

    En outre, on dispose les points d'injection définis par la disposition des divers injecteurs de combustible 3 et d'oxydant 5 et 6, de telle sorte que la distance D entre le point d'injection de chaque jet principal d'oxydant 7, 8 satisfait par rapport au point d'injection du jet de combustible 4 à la relation suivante : D A > 5 In addition, there are the injection points defined by the arrangement of the various fuel injectors 3 and of oxidant 5 and 6, so that the distance D between the injection point of each main jet of oxidant 7, 8 satisfied with respect to the injection point of the fuel jet 4 with the following relation: D AT > 5

    Dans cette relation (I), D représente la distance minimale entre le bord externe du jet d'oxydant considéré, 7 ou 8, et le bord externe du jet de combustible 4 à leurs points respectifs d'injection (voir figure 2), et A représente la section du jet principal de l'oxydant considéré 7 ou 8 à son point d'injection.In this relation (I), D represents the minimum distance between the outer edge of the oxidant jet considered, 7 or 8, and the outer edge of the fuel 4 at their respective injection points (see Figure 2), and A represents the section of the main jet of the oxidant considered 7 or 8 at its point injection.

    Ainsi, les jets d'oxydant 7 et 8 et de combustible 4 ne commencent à se mélanger qu'à partir d'une distance L des points d'injection respectifs, dans des zones 30, 31 de mélange représentées en gris. La séparation des jets sur cette distance L permet à ceux-ci, notamment aux jets 7 et 8 principaux d'oxydant, d'entraíner une quantité importante du fluide environnant sensiblement inerte, comme cela est représenté par des flèches 32 sur la figure 1. Cette quantité entraínée du fluide environnant est généralement supérieure à cinq, de préférence à dix fois le débit du jet entraínant ce fluide. Dans le cas où les jets sont injectés dans une chambre de combustion fermée, ce fluide environnant est composé principalement de produits de combustion.Thus, the jets of oxidant 7 and 8 and of fuel 4 do not begin to mix only from a distance L from the injection points respective, in mixing zones 30, 31 shown in gray. The separation of the jets over this distance L allows them, in particular to the jets 7 and 8 main oxidant, cause a significant amount of fluid surrounding substantially inert, as shown by arrows 32 in Figure 1. This entrained amount of the surrounding fluid is generally more than five, preferably ten times the jet flow causing this fluid. In the event that the jets are injected into a closed combustion, this surrounding fluid is mainly composed of combustion products.

    Du fait que le fluide environnant ne participe pas activement à la combustion et grâce à la quantité importante entraínée de ce fluide, on dilue le mélange oxydant / combustible dans les zones de mélange 30 et 31, et on agrandit le volume occupé par la zone principale 2 de combustion. Ceci a pour effet d'homogénéiser la distribution spatiale du champ de température dans cette zone principale 2 de combustion et de diminuer la température moyenne dans celle-ci, de sorte que l'émission des oxydes d'azote est efficacement réduite.Because the surrounding fluid does not actively participate in the combustion and thanks to the large quantity entrained in this fluid, the oxidant / fuel mixture in mixing zones 30 and 31, and increases the volume occupied by the main combustion zone 2. This has for effect of homogenizing the spatial distribution of the temperature field in this main combustion zone 2 and decrease the average temperature in it, so that the emission of nitrogen oxides is efficiently scaled down.

    Pour optimiser d'avantage les conditions de combustion, la distance D satisfait en outre à la relation suivante : D Ac > 5 où Ac représente la section du jet de combustible à son point d'injection.To further optimize the combustion conditions, the distance D also satisfies the following relationship: D AT vs > 5 where A c represents the section of the fuel jet at its injection point.

    Pour le démarrage et ensuite pour la stabilisation de la combustion, on injecte en outre dans la zone principale 2 de combustion, à une distance Ds du jet 4 associé de combustible, le jet auxiliaire d'oxydant 14. La stabilisation de la combustion dans la zone principale 2 est assurée par la présence de la zone auxiliaire 2A de combustion en amont, qui assure ainsi une région d'inflammation stable du mélange oxydant/combustible dans la zone 2. Ds satisfait à la relation suivante : Ds As < 5 For the start-up and then for the stabilization of the combustion, the auxiliary oxidant jet 14 is also injected into the main combustion zone 2, at a distance D s from the associated jet 4 of fuel. Stabilization of the combustion in the main zone 2 is provided by the presence of the auxiliary combustion zone 2A upstream, which thus ensures a region of stable ignition of the oxidant / fuel mixture in the zone 2. D s satisfies the following relationship: D s AT s <5

    Dans cette relation (III), Ds représente la distance minimale entre le bord externe du jet auxiliaire d'oxydant 14 considéré et le bord externe du jet associé de combustible 4, à leurs points respectifs d'injection, et As représente la section du jet auxiliaire d'oxydant 14 à son point d'injection.In this relation (III), D s represents the minimum distance between the external edge of the auxiliary oxidant jet 14 considered and the external edge of the associated fuel jet 4, at their respective injection points, and A s represents the section of the auxiliary oxidant jet 14 at its injection point.

    Bien entendu, dans toutes ces relations, les sections A, Ac, et As des jets à leurs points respectifs d'injection sont déterminées en prenant en compte leurs formes particulières géométriques.Of course, in all these relationships, the sections A, A c , and A s of the jets at their respective injection points are determined by taking into account their particular geometric shapes.

    En particulier, si par exemple la taille de la section d'un des jets principaux d'oxydant est supérieure à celle de l'autre, les distances D minimales entres les bords externes des jets respectifs d'oxydant et de combustible peuvent également être différentes, à savoir un jet d'oxydant ayant une section plus petite peut être disposé plus près du jet de combustible que celui ayant une section plus grande.In particular, if for example the section size of one of the jets main oxidant is greater than that of the other, the distances D minimum between the outer edges of the respective oxidant and fuel can also be different, namely a jet of oxidant having a smaller section can be arranged closer to the fuel jet than the one with a larger section.

    De plus, on peut prévoir plusieurs injecteurs de jets de combustible et plusieurs injecteurs de jets principaux d'oxydant. Dans ce cas, pour satisfaire à la relation (I), il faut considérer pour chaque jet principal d'oxydant le jet de combustible le plus proche de lui. In addition, several jet injectors can be provided. fuel and several main oxidant jet injectors. In that case, to satisfy relation (I), consider for each main throw oxidizing the closest jet of fuel to it.

    Dans une configuration minimale de l'invention, on ne prévoit qu'un jet de combustible, un jet d'oxydant principal et un jet d'oxydant auxiliaire, la disposition des jets satisfaisant aux relations (I), (II) et (III).In a minimal configuration of the invention, no provision is made than a fuel jet, a main oxidant jet and an oxidant jet auxiliary, the arrangement of the jets satisfying relations (I), (II) and (III).

    En variante à l'installation des figures 1 et 2 et comme cela est représenté sur la figure 3, on peut par exemple prévoir deux injecteurs supplémentaires 37 et 38 de jets principaux d'oxydant. Ces injecteurs 37 et 38 ainsi que les injecteurs 5 et 6 sont disposés symétriquement autour de l'injecteur 3 du jet central 4 de combustible. Une telle configuration permet de réaliser une installation de combustion plus compacte du fait que l'on peut choisir des injecteurs d'oxydant principal de diamètre réduit et disposés plus près de l'injecteur de combustible tout en satisfaisant à la relation (I).As an alternative to the installation of Figures 1 and 2 and as is shown in Figure 3, we can for example provide two injectors additional 37 and 38 of main oxidant jets. These injectors 37 and 38 as well as the injectors 5 and 6 are arranged symmetrically around the injector 3 of the central fuel jet 4. Such a configuration allows make a more compact combustion plant because it can choose main oxidant injectors of reduced diameter and arranged more near the fuel injector while satisfying equation (I).

    La figure 4 montre en une vue de face identique à celle de la figure 2 une autre variante d'une installation 1 pour la mise en oeuvre du procédé selon l'invention.Figure 4 shows in a front view identical to that of the Figure 2 another variant of an installation 1 for the implementation of process according to the invention.

    L'installation de cette variante comprend trois injecteurs 50, 51 et 52 de trois jets d'un premier combustible, par exemple du gaz naturel, qui sont coplanaires avec des injecteurs 55 et 56 de jets principaux d'oxydant disposés diamétralement opposés par rapport aux injecteurs 50, 51 et 52, et un injecteur 53 d'un jet d'un second combustible, par exemple du fioul, disposé au dessus des trois injecteurs 50, 51 et 52 des jets du premier combustible et permettant d'alterner le combustible utilisé.The installation of this variant comprises three injectors 50, 51 and 52 of three jets of a first fuel, for example natural gas, which are coplanar with injectors 55 and 56 of main oxidant jets arranged diametrically opposite with respect to the injectors 50, 51 and 52, and an injector 53 of a jet of a second fuel, for example fuel oil, disposed above of the three injectors 50, 51 and 52 of the jets of the first fuel and allowing to alternate the fuel used.

    Bien entendu, les injecteurs 55 et 56 et par conséquent les jets d'oxydant principal projetés dans la zone de combustion par ceux-ci se trouvent, à leurs points respectifs d'injection, à une distance D minimale entre les bords externes par rapport au jet de combustible le plus proche, c'est-à-dire le jet projeté par l'injecteur 50 en ce qui concerne l'injecteur principal 55 et l'injecteur 52 en ce qui concerne l'injecteur principal 56, de façon à respecter les relations (I) et (II). Of course, the injectors 55 and 56 and therefore the jets main oxidant sprayed into the combustion zone by them find, at their respective injection points, at a minimum distance D between the outer edges with respect to the nearest fuel jet, i.e. the jet projected by the injector 50 with respect to the main injector 55 and the injector 52 with respect to the main injector 56, so as to respect relations (I) and (II).

    De plus, deux injecteurs 57 et 58 de jets auxiliaires d'oxydant sont disposés au dessus des trois injecteurs 50, 51 et 52 des jets de combustible dont l'un 57 est associé aux injecteurs 50, 51 et 53 et dont l'autre 58 est associé aux injecteurs 51, 52 et 53. Ces injecteurs auxiliaires 57 et 58 se trouvent à une distance Ds minimale entre les bords externes des jets de combustible de façon à respecter la relation (III).In addition, two injectors 57 and 58 of auxiliary oxidant jets are disposed above the three injectors 50, 51 and 52 of the fuel jets, one of which 57 is associated with the injectors 50, 51 and 53 and the other of which 58 is associated with the injectors 51, 52 and 53. These auxiliary injectors 57 and 58 are located at a minimum distance D s between the external edges of the fuel jets so as to respect the relationship (III).

    Bien entendu, dans toutes les variantes représentées sur les figures 1 à 4, on peut également envisager d'inverser l'alimentation des injecteurs de sorte que l'on injecte des jets d'oxydant à la place des jets de combustible et vice versa du moment que les relations (I), (II) et (III) sont respectées.Of course, in all the variants shown on the Figures 1 to 4, one can also consider reversing the supply of injectors so that we inject oxidant jets instead of the jets of combustible and vice versa as long as the relations (I), (II) and (III) are respected.

    La figure 5 montre à titre indicatif un graphique représentant un résultat obtenu avec le procédé selon l'invention mis en oeuvre à l'aide d'une installation du type représentée sur les figures 1 et 2 et dans laquelle on pouvait ajuster la distance D définie plus haut des jets d'oxydant principal par rapport au jet central de combustible. Ce graphique montre la quantité d'oxydes d'azote (NOx) produite lors de la combustion en fonction du paramètre D/√A défini plus haut.FIG. 5 shows by way of indication a graph representing a result obtained with the method according to the invention implemented using an installation of the type shown in FIGS. 1 and 2 and in which the distance D defined could be adjusted higher of the main oxidant jets relative to the central fuel jet. This graph shows the quantity of nitrogen oxides (NO x ) produced during combustion as a function of the parameter D / √A defined above.

    Sur ce graphique, on voit que la formation des oxydes d'azotes diminue considérablement en fonction du paramètre D/√A. On voit clairement que pour les jets principaux d'oxydant dont la disposition respecte la relation D A > 5, la réduction des émissions d'oxydes d'azote est importante.On this graph, we see that the formation of nitrogen oxides decreases considerably depending on the parameter D / √A. It is clearly seen that for the main oxidant jets whose arrangement respects the relationship D AT > 5, reducing nitrogen oxide emissions is important.

    Grâce au procédé selon l'invention et en particulier à la disposition des jets principaux et auxiliaires d'oxydant par rapport aux injecteurs de combustible, on obtient une combustion stable et une émission réduite des oxydes d'azote.Thanks to the process according to the invention and in particular to the arrangement of the main and auxiliary oxidant jets relative to the fuel injectors, stable combustion and emission reduced nitrogen oxides.

    Claims (10)

    1. Combustion process for burning a fuel, in which at least one fuel jet (4) and some distance therefrom at least one main jet of an oxidizer (7, 8) are simultaneously injected into a main combustion zone (2), in which process the point of injection of each main oxidizer jet (7, 8) with respect to the point of injection of the fuel jet (4) closest to it is arranged a distance D away satisfying at least one of the following relations: D A >5 (and preferably >10) and/or D B >5(and preferably >10) D being defined as the minimum distance between the outer edge of the relevant oxidizer jet (7, 8) and the outer edge of the fuel jet (4) closest to it, at their respective points of injection, and A and B being respectively the cross section of the main jet of the oxidizer (7, 8) and the cross section of the fuel jet (4), the cross sections being considered at the point of injection of the jets, in such a way as to keep the fuel (4) and main oxidizer (7, 8) jets separated until the said at least one main oxidizer jet (7, 8) and/or the fuel jet (4) has entrained a quantity of a substantially inert surrounding fluid so as to obtain substantially uniform combustion, characterized in that at least one auxiliary jet of an oxidizer (14) is injected into an auxiliary combustion zone (2A) situated upstream of the said main combustion zone (2) so as to stabilize the combustion in the said main combustion zone (2), the point of injection of the said auxiliary oxidizer jet (14) being arranged a distance Ds away from the associated fuel jet (4), Ds satisfying the following relation: Ds As < 5 Ds being the minimum distance.between the outer edge of the relevant auxiliary oxidizer jet (14) and the outer edge of the associated fuel jet (4), at their respective points of injection, and As being the cross section of the relevant auxiliary oxidizer jet at its point of injection.
    2. Process according to Claim 1, characterized in that the quantity of surrounding fluid entrained is greater than five, even more preferably than ten times its own flow rate.
    3. Process according to either of Claims 1 and 2, characterized in that the local flow rate of oxidizer injected by the said main and auxiliary oxidizer jets (7, 8, 14) is adjusted to a value above the stoichiometric flow rate of oxidizer required to burn all the fuel injected into the combustion zone by the said at least one fuel jet (4).
    4. Process according to one of Claims 1 to 3, characterized in that the flow rate of oxidizer injected by the said at least one auxiliary jet (14) is adjusted to a value below 30%, preferably between 2% and 15% of the total flow rate of oxidizer injected into the combustion zone.
    5. Process according to one of Claims 1 to 4, characterized in that the total flow rate of oxidizer injected by the said main and auxiliary oxidizer jets (7, 8, 14) is adjusted to a value above the stoichiometric flow rate of oxidizer required to burn all the fuel injected into the combustion zone by the said at least one fuel jet (4).
    6. Process according to one of Claims 1 to 5, characterized in that the flow rate of oxidizer injected by the said at least one auxiliary jet (14) is adjusted to a value below 30%, preferably between 2% and 15% of the total flow rate of oxidizer injected into the combustion zone (2).
    7. Process according to one of Claims 1 to 6, characterized in that several main oxidizer jets (5, 6, 37, 38) are injected symmetrically about the said at least one fuel jet (4).
    8. Process according to Claim 7, characterized in that two main oxidizer jets (5, 6) arranged diametrically opposite with respect to at least one central fuel jet (4) are injected into the said combustion zone.
    9. Process according to Claim 8, characterized in that three central fuel jets (50, 51, 52) which are coplanar with the two main oxidizer jets (55, 56) arranged diametrically opposite with respect to the three central fuel jets (50, 51, 52) are injected into the said combustion zone.
    10. Process according to one of Claims 1 to 9, characterized in that at least one jet of a first fuel (50, 51, 52), in particular natural gas, and at least one jet of a second fuel (53), in particular fuel oil, are injected into the said combustion zone.
    EP99402117A 1998-09-02 1999-08-25 Combustion process for burning a fuel Revoked EP0984223B1 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    FR9810966A FR2782780B1 (en) 1998-09-02 1998-09-02 COMBUSTION METHOD FOR BURNING A FUEL
    FR9810966 1998-09-02

    Publications (2)

    Publication Number Publication Date
    EP0984223A1 EP0984223A1 (en) 2000-03-08
    EP0984223B1 true EP0984223B1 (en) 2004-05-19

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    ID=9530048

    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP99402117A Revoked EP0984223B1 (en) 1998-09-02 1999-08-25 Combustion process for burning a fuel

    Country Status (9)

    Country Link
    US (1) US6196831B1 (en)
    EP (1) EP0984223B1 (en)
    JP (1) JP2000088212A (en)
    CN (1) CN1247290A (en)
    AT (1) ATE267362T1 (en)
    DE (1) DE69917395T2 (en)
    ES (1) ES2221335T3 (en)
    FR (1) FR2782780B1 (en)
    ID (1) ID23833A (en)

    Families Citing this family (21)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    FR2795716B1 (en) * 1999-07-02 2001-08-03 Air Liquide PROCESS FOR CALCINATION OF A MATERIAL BASED ON ORE
    US6910878B2 (en) * 2003-06-19 2005-06-28 Praxair Technology, Inc. Oxy-fuel fired process heaters
    FR2863689B1 (en) * 2003-12-16 2006-05-05 Air Liquide A TIRED COMBUSTION PROCESS USING PREHEATED OXIDANT
    FR2863692B1 (en) * 2003-12-16 2009-07-10 Air Liquide TIRED COMBUSTION PROCESS WITH OPTIMIZED INJECTION OF PRIMARY OXIDANT
    US7185830B2 (en) * 2004-06-18 2007-03-06 Malcolm David B Uniform droplet spray nozzle for liquids
    US20070152083A1 (en) * 2004-06-18 2007-07-05 Malcolm David B Uniform droplet spray nozzle for liquids
    SE528808C2 (en) * 2004-09-15 2007-02-20 Aga Ab Combustion process and burner
    US20060275724A1 (en) * 2005-06-02 2006-12-07 Joshi Mahendra L Dynamic burner reconfiguration and combustion system for process heaters and boilers
    SE0501840L (en) * 2005-08-19 2007-02-20 Aga Ab Procedure as well as for monitoring a burner
    AU2005337795A1 (en) * 2005-10-28 2007-05-03 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process and apparatus for low-NOx combustion
    FR2903762B1 (en) * 2006-07-13 2008-09-05 Air Liquide BURNER AND METHOD FOR ALTERNATING OXYCOMBUSTION AND AEROCOMBUSTION
    FR2917155A1 (en) * 2007-06-08 2008-12-12 Saint Gobain Emballage Sa COMBUSTION DILUTED
    EP2080952A1 (en) * 2008-01-17 2009-07-22 L'AIR LIQUIDE, Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude Burner and method for alternately implementing an oxycombustion and an air combustion
    SE533967C2 (en) * 2009-03-20 2011-03-15 Aga Ab Process for homogenizing the heat distribution and reducing the amount of NOx in combustion
    US20120199273A1 (en) * 2009-11-19 2012-08-09 Porter Shannon C Method of Making a Pneumatic Innerliner
    US9033259B2 (en) 2010-12-23 2015-05-19 General Electric Company Method and system for mixing reactor feed
    EP2479492A1 (en) 2011-01-21 2012-07-25 Technip France Burner, furnace
    EP2766665A4 (en) * 2011-10-03 2015-10-14 Saint Gobain Emballage Reduced emissions combustor
    US9228744B2 (en) 2012-01-10 2016-01-05 General Electric Company System for gasification fuel injection
    FR2986855A1 (en) * 2012-02-10 2013-08-16 Air Liquide Burner for use in vertical wall of boiler, has primary, secondary and fuel injectors mounted in main passage such that primary and secondary noses are drowned in dilution gas flowing in passage during operation of burner fuel noses
    US9545604B2 (en) 2013-11-15 2017-01-17 General Electric Company Solids combining system for a solid feedstock

    Family Cites Families (12)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    JPS5819929B2 (en) * 1978-07-11 1983-04-20 新日本製鐵株式会社 Low NO↓x burner
    JPS55143307A (en) * 1979-04-23 1980-11-08 Kobe Steel Ltd Double combustion apparatus
    DE2951796C2 (en) * 1978-12-21 1982-11-04 Kobe Steel, Ltd., Kobe, Hyogo Gaseous or liquid fuel burners for minimal NO &darr; x &darr; emissions
    US4541796A (en) * 1980-04-10 1985-09-17 Union Carbide Corporation Oxygen aspirator burner for firing a furnace
    US4378205A (en) * 1980-04-10 1983-03-29 Union Carbide Corporation Oxygen aspirator burner and process for firing a furnace
    US4988285A (en) 1989-08-15 1991-01-29 Union Carbide Corporation Reduced Nox combustion method
    JPH07190319A (en) * 1993-12-06 1995-07-28 Bloom Eng Co Inc Air multistage supply type burner and its combustion method
    JP3254337B2 (en) * 1994-09-24 2002-02-04 トヨタ自動車株式会社 Low NOx burner
    EP0754912B1 (en) * 1995-07-17 2004-06-09 L'air Liquide, S.A. à Directoire et Conseil de Surveillance pour l'Etude et l'Exploitation des Procédés Georges Claude Combustion process and apparatus therefor containing separate injection of fuel and oxidant streams
    JP3557028B2 (en) * 1996-02-14 2004-08-25 Ｊｆｅスチール株式会社 Combustion burner and combustion method in furnace
    US5839890A (en) * 1996-09-19 1998-11-24 Praxair Technology, Inc. Condensation free nozzle
    US5975886A (en) * 1996-11-25 1999-11-02 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Combustion process and apparatus therefore containing separate injection of fuel and oxidant streams

    Also Published As

    Publication number Publication date
    JP2000088212A (en) 2000-03-31
    CN1247290A (en) 2000-03-15
    DE69917395D1 (en) 2004-06-24
    ATE267362T1 (en) 2004-06-15
    FR2782780A1 (en) 2000-03-03
    FR2782780B1 (en) 2000-10-06
    DE69917395T2 (en) 2005-06-02
    EP0984223A1 (en) 2000-03-08
    ES2221335T3 (en) 2004-12-16
    US6196831B1 (en) 2001-03-06
    ID23833A (en) 2000-05-25

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