Particulate Fuel Combustion Process and Furnace

Abstract

The present invention provides a combustion furnace that 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 main particulate fuel burner mounted in a chamber wall and adapted to generate in the combustion zone a main flame directed away from the chamber wall by injecting oxidant in gaseous form and fuel in particulate form into the combustion zone for combustion therein. With regard to the combustion chamber, the main particulate fuel burner has associated therewith at least one auxiliary burner mounted in the burner wall. The auxiliary burner is located in the vicinity of the main particulate fuel burner and is adapted to generate an auxiliary flame in the combustion zone located proximate the chamber wall and at least partially directed towards the main particulate fuel burner.

1 . 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 main particulate fuel burner mounted in a chamber wall and adapted to generate in the combustion zone a main flame directed away from the chamber wall by injecting oxidant in gaseous form and fuel in particulate form into the combustion zone for combustion therein,   
       wherein the main particulate fuel burner has associated therewith at least one auxiliary burner mounted in the burner wall, the auxiliary burner being located in the vicinity of the main particulate fuel burner and being adapted to generate an auxiliary flame in the combustion zone located proximate the chamber wall and at least partially directed towards the main particulate fuel burner. 
     
     
         2 . The combustion furnace of  claim 1 , wherein the main particulate fuel burner has at least two auxiliary burners associated therewith. 
     
     
         3 . The combustion furnace of  claim 1 , wherein the auxiliary burner is associated with more then one main particulate fuel burner. 
     
     
         4 . The combustion furnace of  claim 1 , wherein the nominal power of the main particulate fuel burner is greater than the nominal power of the auxiliary burner. 
     
     
         5 . The combustion furnace of  claim 4 , wherein the nominal power of the main particular fuel burner is at least 50% greater than the nominal power of the auxiliary burner. 
     
     
         6 . The combustion furnace of  claim 4 , wherein the nominal power of the main particulate fuel burner is at least twice the nominal power of the auxiliary burner. 
     
     
         7 . The combustion furnace of  claim 1 , wherein the main particulate fuel burner is a solid particulate fuel burner or a liquid particulate fuel burner. 
     
     
         8 . The combustion furnace of  claim 1 , wherein the combustion furnace includes a multitude of main particulate fuel burners, each main particulate fuel burner having at least one auxiliary burner associated therewith. 
     
     
         9 . The combustion furnace of claim according to  claim 8 , having a multitude of main particulate fuel burners in one chamber wall. 
     
     
         10 . The combustion furnace of  claim 8 , having at least one main particulate fuel burner in a first chamber wall and at least one particulate fuel burner in a second chamber wall positioned opposite the first chamber wall across the combustion zone. 
     
     
         11 . The combustion furnace of  claim 9 , having at least one main particulate fuel burner in a first chamber wall and at least one particulate fuel burner in a second chamber wall positioned opposite the first chamber wall across the combustion zone. 
     
     
         12 . A process of operating a combustion furnace, wherein the 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 main particulate fuel burner mounted in a chamber wall and adapted to generate in the combustion zone a main flame directed away from the chamber wall into which the main burner is mounted by injecting oxidant in gaseous form and fuel in particulate form into the combustion zone for combustion therein,   
       the process comprising: injecting oxidant in gaseous form and fuel in particulate form into the combustion zone for combustion by means of the main particulate fuel burner so as to generate a main flame in the combustion zone directed away from the chamber wall, the main flame having a root adjacent the main particulate fuel burner, 
       wherein the main particulate fuel burner has associated therewith at least one auxiliary burner mounted in the chamber wall in the vicinity of the main particulate fuel burner, and the process further comprising the step of: generating an auxiliary flame in the combustion zone by means of the at least one auxiliary burner associated with the main particulate fuel burner, the auxiliary flame being located proximate the chamber wall and at least partially directed towards the root of the main flame generated by the main particulate fuel burner. 
     
     
         13 . The process of  claim 12 , wherein the main particulate fuel burner has at least two auxiliary burners associated therewith. 
     
     
         14 . The process of  claim 12 , wherein the auxiliary burner is associated with more than one main particulate fuel burner. 
     
     
         15 . The process of  claim 13 , wherein the auxiliary burner is associated with more than one main particulate fuel burner. 
     
     
         16 . The process of  claim 12 , wherein the auxiliary flame has a flame axis substantially perpendicular to the chamber wall a flame opening of at least 110°. 
     
     
         17 . The process of  claim 16 , wherein the auxiliary flame has a flame axis substantially perpendicular to the chamber wall a flame opening of at least 130°. 
     
     
         18 . The process of  claim 17 , wherein the auxiliary flame has a flame axis substantially perpendicular to the chamber wall a flame opening of at least 150°. 
     
     
         19 . The process of  claim 12 , wherein the auxiliary flame has a flame axis forming a sharp angle with the chamber wall. 
     
     
         20 . The process of  claim 19 , wherein the sharp angle with the chamber wall is not more than 60° with the chamber wall. 
     
     
         21 . The process of  claim 20 , the sharp angle with the chamber wall is not more than 30° with the chamber wall. 
     
     
         22 . The process of  claim 12 , wherein the fuel injected by the main particulate fuel burner is a particulate solid fuel or the fuel burners is a particulate liquid fuel. 
     
     
         23 . The process of  claim 12 , wherein the main particulate fuel burners are oxy-fuel burners.