Particulate Fuel Combustion Process and Furnace

Abstract

The present invention provides a process for operating a combustion furnace, wherein the combustion furnace comprises a combustion chamber defining a combustion zone within the combustion chamber and having at least one chamber wall facing the combustion zone, and at least one particulate fuel burner mounted in a chamber wall and adapted to generate a flame in the combustion zone by injecting oxidant in gaseous form and fuel in particulate form into the combustion zone for combustion therein. In the process, at least one particulate fuel burner is operated so as to alternate between a first phase in which the burner generates a wide flame proximate the chamber wall into which the burner is mounted and a second phase in which the burner generates a narrower flame directed away from the chamber wall into which the burner is mounted.

1 - 16 . (canceled) 
     
     
         17 . A process of operating a combustion furnace, comprising the steps of:
 providing a combustion furnace comprising:
 a combustion chamber defining a combustion zone within the combustion chamber and having at least one chamber wall facing the combustion zone, and 
 at least one particulate fuel burner mounted in a chamber wall and adapted to generate a flame in the combustion zone by injecting oxidant in gaseous form and fuel in particulate form into the combustion zone for combustion therein; and 
   performing alternating first and second steps, wherein:
 in a first phase, at least one of the at least one particulate fuel burner is operated to generate a wide flame proximate the chamber wall into which it is mounted, and 
 in a second phase, the at least one of the at least one particulate fuel burner is operated to generate a narrower flame directed away from the chamber wall into which it is mounted. 
   
     
     
         18 . The process of  claim 17 , wherein the furnace comprises several particulate fuel burners, each mounted in a chamber wall and adapted to generate a flame in the combustion zone by injecting oxidant in gaseous form and fuel in particulate form into the combustion zone for combustion therein, each particulate fuel burner being operated so as to alternate between the first phase and the second phase and wherein at any time during the process a first portion of the particulate fuel burners operate in the first phase, while the remaining portion of the particulate fuel burners operate in the second phase. 
     
     
         19 . The process of  claim 18 , wherein at any time during the process at least half of the particulate fuel burners operate in the second phase. 
     
     
         20 . The process of  claim 19 , wherein at any time during the process at least two thirds of the particulate fuel burners operate in the second phase. 
     
     
         21 . The process of  claim 18 , wherein the furnace comprises a multitude of particulate fuel burners mounted in one chamber wall and adapted to generate a flame in the combustion zone by injecting oxidant in gaseous form and fuel in particulate form into the combustion zone for combustion therein, each particulate fuel burner of the multitude being operated so as to alternate between the first phase and the second phase and wherein at any time during the process a first portion of the multitude of particulate fuel burners mounted in the one chamber wall operate in the first phase, while the remaining portion of the multitude of particulate fuel burners mounted in the one chamber wall operate in the second phase. 
     
     
         22 . The process of  claim 18 , wherein the furnace comprises one or more pairs of particulate fuel burners, each pair consisting of a first particulate fuel burner and a second particulate fuel burner, the second particulate fuel burner being positioned opposite the first particulate fuel burner and when the first particulate fuel burner of the pair operates in the first phase, the second particulate fuel burner of the pair operates in the second phase and, when the first particulate fuel burner of the pair operates in the second phase, the second particulate fuel burner of the pair operates in the first phase. 
     
     
         23 . The process of  claim 18 , wherein the furnace comprises a first multitude of particulate fuel burners mounted in a first chamber wall and a second multitude of particulate fuel burners mounted in a second chamber wall opposite the first chamber wall, the particulate fuel burners being adapted to generate a flame in the combustion zone by injecting oxidant in gaseous form and fuel in particulate form into the combustion zone for combustion therein, and being operated so as to alternate between the first phase and the second phase. 
     
     
         24 . The process of  claim 23 , wherein, at any moment during the process:
 either all the particulate fuel burners of the first multitude simultaneously operate in the first phase while all the particulate fuel burners of the second multitude operate in the second phase, or   all the particulate fuel burners of the first multitude simultaneously operate in the second phase while all the particulate fuel burners of the second multitude simultaneously operate in the first phase.   
     
     
         25 . The process of  claim 23 , wherein the furnace comprises several pairs of particulate fuel burners, each pair consisting of a first particulate fuel burner belonging to the first multitude of particulate fuel burners and a second particulate fuel burner belonging to the second multitude of particulate fuel burners, the first and second particulate fuel burners of each pair being positioned opposite one another, wherein:
 when the first particulate fuel burner of a pair operates in the first phase, the second particulate fuel burner of the pair operates in the second phase; and   when the first particulate fuel burner of the pair operates in the second phase, the second particulate fuel burner of the pair operates in the first phase.   
     
     
         26 . The process of  claim 25 , wherein, at any time during the method, a first portion of the first particulate fuel burners operate in the first phase and the remaining first particulate fuel burners operate in the second phase. 
     
     
         27 . The process of  claim 23 , wherein the first and second walls are lateral walls of the combustion chamber. 
     
     
         28 . The process of  claim 25 , wherein the first and second walls are lateral walls of the combustion chamber. 
     
     
         29 . The process of  claim 17 , wherein the fuel injected by the particulate fuel burners is a particulate solid fuel. 
     
     
         30 . The process of  claim 17 , wherein the fuel injected by the particulate fuel burners is a particulate liquid fuel. 
     
     
         31 . The process of  claim 17 , wherein the particulate fuel burners are oxy-fuel burners. 
     
     
         32 . The process of  claim 17 , wherein the furnace is a glass-melting furnace, a glass feeder or forehearth, a tunnel calcination furnace or a reheat furnace.