Staged Combustion System With Ignition-Assisted Fuel Lances

Abstract

Combustion system comprising a furnace having a thermal load and a combustion atmosphere, wherein the thermal load and combustion atmosphere are disposed within the furnace; one or more fuel lances adapted to inject fuel into the combustion atmosphere; and one or more igniters associated with the one or more fuel lances and adapted to ignite the fuel injected by the one or more fuel lances.

1 . A combustion system comprising 
 (a) a furnace having a thermal load and a combustion atmosphere disposed therein;    (b) one or more fuel lances adapted to inject fuel into the combustion atmosphere; and    (c) one or more igniters associated with the one or more fuel lances and adapted to ignite the fuel injected by the one or more fuel lances into the combustion atmosphere.    
   
   
       2 . The system of  claim 1  wherein the one or more igniters are selected from the group consisting of intermittent spark igniters, continuous spark igniters, DC arc plasmas, microwave plasmas, RF plasmas, high energy laser beams, and oxidant-fuel pilot burners.  
   
   
       3 . The system of  claim 1  wherein at least one of the igniters is disposed adjacent to a fuel lance and is adapted to ignite fuel discharged therefrom.  
   
   
       4 . The system of  claim 1  wherein at least one of the igniters is integrated into a fuel lance and is adapted to ignite fuel discharged therefrom.  
   
   
       5 . The system of  claim 1  wherein the number of fuel lances is equal to or less than the number of igniters.  
   
   
       6 . A combustion system comprising 
 (a) a furnace comprising an enclosure and a thermal load disposed within the enclosure;    (b) one or more oxidant gas injectors mounted in the enclosure and adapted to introduce an oxidant gas into the furnace;    (c) one or more fuel lances mounted in the enclosure and spaced apart from the one or more oxidant gas injectors, wherein the one or more fuel lances are adapted to inject fuel into the furnace; and    (d) one or more igniters associated with the one or more fuel lances and adapted to ignite the fuel injected by the fuel lances.    
   
   
       7 . The system of  claim 6  wherein the one or more igniters are selected from the group consisting of intermittent spark igniters, continuous spark igniters, DC arc plasmas, microwave plasmas, RF plasmas, high energy laser beams, and oxidant-fuel pilot burners.  
   
   
       8 . The system of  claim 6  wherein at least one of the igniters is adjacent to a fuel lance and is adapted to ignite fuel discharged therefrom.  
   
   
       9 . The system of  claim 6  wherein at least one of the igniters is integrated into a fuel lance and is adapted to ignite fuel discharged therefrom.  
   
   
       10 . The system of  claim 6  wherein the number of fuel lances is equal to or less than the number of igniters.  
   
   
       11 . The system of  claim 6  wherein the distance between the periphery of one of the one or more oxidant gas injectors and the periphery of an adjacent fuel lance is in the range of 2 to 50 inches.  
   
   
       12 . A combustion system comprising 
 (a) a furnace having a thermal load and a combustion atmosphere disposed therein;    (b) a central burner having an axis, a primary fuel inlet, an oxidant gas inlet, and a combustion gas outlet adapted to introduce the combustion gas into the furnace;    (c) one or more staging fuel lances disposed radially from the axis of the central burner and adapted to inject a staging fuel into the combustion atmosphere in the furnace; and    (d) one or more igniters associated with the one or more staging fuel lances and adapted to ignite the staging fuel injected therefrom.    
   
   
       13 . The system of  claim 12  wherein the one or more igniters are selected from the group consisting of intermittent spark igniters, continuous spark igniters, DC arc plasmas, microwave plasmas, RF plasmas, high energy laser beams, and oxidant-fuel pilot burners.  
   
   
       14 . The system of  claim 12  wherein at least one of the igniters is adjacent to a staging fuel lance and is adapted to ignite fuel discharged therefrom.  
   
   
       15 . The system of  claim 12  wherein at least one of the igniters is integrated into a staging fuel lance and is adapted to ignite fuel discharged therefrom.  
   
   
       16 . The system of  claim 12  wherein the number of staging fuel lances is equal to or less than the number of igniters.  
   
   
       17 . The system of  claim 12  which further comprises main fuel piping adapted to provide the primary fuel to the central burner and staging fuel piping adapted to provide the staging fuel to the one or more staging fuel lances.  
   
   
       18 . The system of  claim 17  wherein the primary fuel to the central burner and the staging fuel to the one or more staging fuel lances are identical in composition.  
   
   
       19 . The system of  claim 17  wherein the primary fuel to the central burner and the staging fuel to the one or more staging fuel lances are different in composition.  
   
   
       20 . The system of  claim 12  wherein the one or more staging fuel lances are disposed outside of the central burner and are disposed radially from the axis of the central burner.  
   
   
       21 . A combustion process comprising 
 (a) providing a combustion system comprising 
 (1) a furnace having a thermal load and a combustion atmosphere disposed therein;  
 (2) a central burner having an axis, a primary fuel inlet, an oxidant gas inlet, and a combustion gas outlet adapted to introduce the combustion gas into the furnace;  
 (3) one or more staging fuel lances disposed radially from the axis of the central burner and adapted to inject a staging fuel into the combustion atmosphere in the furnace; and  
 (4) one or more igniters associated with the one or more staging fuel lances and adapted to ignite the staging fuel discharged therefrom.  
   (b) introducing the oxidant gas through the oxidant gas inlet and injecting fuel through the one or more fuel lances into the combustion atmosphere in the furnace; and    (c) operating the one or more igniters and igniting the fuel from the fuel lances to cause combustion of the fuel with oxygen in the combustion atmosphere.    
   
   
       22 . The process of  claim 21  wherein the fuel is selected from natural gas, refinery offgas, associated gas from crude oil production, and combustible process waste gas  
   
   
       23 . The process of  claim 21  wherein a plurality of fuel lances are used and fuels of different compositions are used in the plurality of fuel lances.  
   
   
       24 . A combustion process comprising 
 (a) providing a combustion system including 
 (1) a furnace having an enclosure with a thermal load and a combustion atmosphere disposed within the enclosure;  
 (2) one or more oxidant gas injectors mounted in the enclosure and adapted to introduce oxygen-containing gas into the furnace;  
 (3) one or more fuel lances mounted in the enclosure and spaced apart from the one or more oxidant gas injectors, wherein the one or more fuel lances are adapted to inject fuel into the furnace; and  
 (4) one or more igniters associated with the one or more fuel lances and adapted to ignite the fuel injected by the fuel lances;  
   (b) injecting the oxygen-containing gas through the one or more oxidant gas injectors into the combustion atmosphere in the furnace;    (c) injecting the fuel through the one or more fuel lances into the combustion atmosphere in the furnace; and    (d) operating the one or more igniters and igniting the fuel from the fuel lances to cause combustion of the fuel with oxygen in the combustion atmosphere.