Burner and Method for Alternately Implementing Oxycombustion and Air Combustion

Abstract

Fuel is combusted with an oxidizer and at least one mainly inert gas, where the mainly inert gas is injected in the form of a divergently swirled jet around the flame and a convergently swirled jet surrounding the divergently swirled jet.

1 - 15 . (canceled) 
   
   
       16 . A method of combustion of at least one fuel using at least one oxidizer and at least one mainly inert gas, comprising the steps of:
 injecting a fuel and an oxidizer to create a flame therefrom;   injecting a mainly inert gas in two jets, wherein:
 the first jet surrounds the flame created by the fuel and the oxidizer, 
 the first jet has a divergent swirl with regard to the flame, 
 the second jet surrounds the first jet, and 
 the second jet has a convergent swirl with regard to the flame. 
   
   
   
       17 . The method of  claim 16 , wherein the oxidizer is an oxygen-containing gas and the mainly inert gas is comprised of gases issuing from a combustion process. 
   
   
       18 . The method of  claim 16 , wherein the oxidizer is an oxygen-containing gas and the mainly inert gas is comprised of recycled gases from combustion of the oxidizer, fuel, and mainly inert gas. 
   
   
       19 . The method of  claim 17 , wherein a flow rate of the first jet accounts for 50 to 97% of a total flow rate of mainly inert gas injected. 
   
   
       20 . The method of  claim 16 , wherein the oxidizer is air and the mainly inert gas is air. 
   
   
       21 . The method of  claim 20 , wherein a flow rate of air injected as oxidizer accounts for 5 to 30% of a total flow rate of air necessary for combustion of the fuel. 
   
   
       22 . The method of  claim 20 , wherein a flow rate of air injected into the first jet accounts for 4 to 25% of a total flow rate of air necessary for combustion of the fuel. 
   
   
       23 . The method of  claim 16 , wherein the oxidizer is an oxygen-containing gas and the mainly inert gas is air. 
   
   
       24 . The method of  claim 16 , wherein swirl rates of each of the jets is between 0.26 and 1.73. 
   
   
       25 . The method of  claim 16 , wherein the jets are ring-shaped. 
   
   
       26 . A burner comprising:
 at least one means for injecting fuel;   at least one means for injecting oxidizer being placed with regard to said at least one means for injecting fuel such that the oxidizer and the fuel are capable of producing a flame; and   first and second means for injecting a mainly inert gas, wherein:
 said first means for injecting the mainly inert gas is suitable for injecting part of the mainly inert gas as a divergently swirled jet surrounding the flame produced by the oxidizer and the fuel, 
 said second means for injecting the mainly inert gas is suitable for injecting part of the mainly inert gas in the form of a convergently swirled jet surrounding the divergently swirled jet. 
   
   
   
       27 . The burner of  claim 26 , wherein:
 said first and second means for injecting mainly inert gas comprise first, second, and third coaxial tubes centred around said means for injecting fuel and said means for injecting oxidizer;   a space between said first and second coaxial tubes allowing passage of part of the mainly inert gas and comprising a swirler suitable for divergently swirling a flow of mainly inert gas passing therethough; and   a space between said second and third coaxial tubes allowing passage of part of the mainly inert gas and comprising a swirler suitable for convergently swirling a flow of mainly inert gas passing therethrough.   
   
   
       28 . The burner of  claim 27 , wherein:
 said at least one means for injecting oxidizer comprises said first coaxial tube surrounding, and coaxial with, an inner tube;   said means for injecting fuel comprises a metal ring drilled with at least one ring of orifices; and   said metal ring being coaxial with, and placed between, said first coaxial tube and said inner tube.   
   
   
       29 . A method for converting an air-fuel burner into an oxygen-fuel burner, the air-fuel burner having at least one means for injecting fuel and at least one means for injecting air, the said means for injecting fuel and air being positioned with regard to one another such that the air and the fuel are capable of producing a flame, said method comprising the steps of:
 providing the air-fuel burner;   providing first and second means for injecting mainly inert gas, said first means for injecting mainly inert gas being suitable for injecting a portion of mainly inert gas in the form of a jet surrounding the flame, said first means for injecting mainly inert gas comprising a swirler suitable for divergently swirling a flow of mainly inert gas passing therethrough, said second means for injecting mainly inert gas being suitable for injecting a portion of the mainly inert gas in the form of a jet surrounding the flame, said second means for injecting mainly inert gas comprising a swirler suitable for convergently swirling the flow of mainly inert gas passing therethrough.   
   
   
       30 . A method for converting a method of air combustion of a fuel in which the fuel and the air are injected into a combustion space in such a way as to create a flame, into an oxycombustion method, comprising the steps of:
 replacing the air with an oxygen-containing gas; and   injecting gases issuing from combustion into the combustion space in the form of first and second jets, the first jet surrounding the flame created by the fuel and the oxygen-containing gas and having divergent swirl with regard to the said flame, the second jet surrounding the first gas jet, the second jet having a convergent swirl with regard to the flame created by the fuel and the oxygen-containing gas.   
   
   
       31 . The method of  claim 16 , wherein the oxidizer is deoiled air and the mainly inert gas is air. 
   
   
       32 . A burner comprising:
 a first oxidizer injection tube;   a fuel injection device disposed coaxially around said first oxidizer injection tube;   a second oxidizer injection tube disposed coaxially around said first oxidizer injection tube and said fuel injection device, said burner capable of producing a flame through injection of oxidizer through said first oxidizer tube, injection of oxidizer through a space between said fuel injection device and said second oxidizer injection tube, and injection of fuel through said fuel injection device;   a first mainly inert gas injection tube disposed coaxially around said second oxidizer injection tube, a first swirler being disposed in a space between said second oxidizer injection tube and said first mainly inert gas injection tube, said first swirler being adapted to inject a divergently swirled jet of mainly inert gas therethrough that surrounds the flame; and   a second mainly inert gas injection tube disposed coaxially around said first mainly inert gas injection tube, a second swirler being disposed in a space between said first mainly inert gas injection tube and said second mainly inert gas injection tube, said second swirler being adapted to inject a convergently swirled jet of mainly inert gas therethrough that surrounds the divergently swirled jet.   
   
   
       33 . The burner of  claim 32 , wherein said fuel injection device comprises a metal ring drilled with at least one ring of orifices. 
   
   
       34 . A method for converting an air-fuel burner into an oxygen-fuel burner, the air fuel-burner having a first oxidizer injection tube, a fuel injection device disposed coaxially around the first oxidizer injection tube, and a second oxidizer injection tube disposed coaxially around the first oxidizer injection tube and the fuel injection device, the burner capable of producing a flame through injection of air through the first oxidizer tube, injection of air through a space between the fuel injection device and the second oxidizer injection tube, and injection of fuel through the fuel injection device, said method comprising the step of:
 providing first and second mainly inert gas injection devices, the first mainly inert gas injection device being suitable for injecting a first jet of mainly inert gas surrounding the flame, and the first mainly inert gas injection device comprising a swirler suitable for divergently swirling the flow of mainly inert gas passing therethrough, the second mainly inert gas injection device being suitable for a jet of injecting mainly inert gas surrounding the first jet, the second mainly inert gas injection device comprising a swirler suitable for convergently swirling the flow of mainly inert gas passing through it.   
   
   
       35 . A method of combustion, comprising the steps of:
 injecting an oxidizer and a fuel into a combustion space to create a flame;   injecting a divergently swirled jet of mainly inert gas surrounding the flame; and   injecting a convergently swirled jet of mainly inerg gas surrounding the divergently swirled jet.