Mixing process for combustion furnaces

Abstract

A system and method for increasing combustion furnace efficiency, including the steps of providing a furnace with a plurality of secondary air injection ducts, asymmetrically positioned in an tangentially reinforcing manner; injecting fuel with substoichiometric primary air through the burners; injecting secondary air through the plurality of secondary air injection ducts; wherein the velocity of the injected air is such that the ratio of the advected air velocity to the furnace width is between about 2 sec −1 to about 150 sec −1 ; thereby increasing combustion efficiency and reactor efficiency via mixing and rotation of the combustion space.

We claim:  
     
         1 . A method for increasing combustion furnace efficiency, comprising: 
 providing a furnace with a plurality of secondary air injection ducts, asymmetrically positioned in an opposing manner;    injecting fuel with primary air through the burners prior to injection of secondary air;    injecting secondary air through the plurality of secondary air injection ducts;    wherein the velocity of the injected air is such that the ratio of the velocity to the furnace width is between about 2 sec −1  to about 150 sec −1 ;    thereby increasing combustion efficiency and furnace efficiency via swirl, peripheral turbulence, and rotation-induce turbulence of the combustion space.    
     
     
         2 . The method of  claim 1 , wherein the temperature of the injected air is between about 40 and about 460 degrees centigrade (10-50% redirected combustion air).  
     
     
         3 . The method of  claim 2 , wherein the temperature of the injected air is between about 76 and about 340 degrees centigrade (20-40% redirected combustion air).  
     
     
         4 . The method of  claim 1 , wherein the system has at least two levels of secondary air ducts for injection of secondary air.  
     
     
         5 . The method of  claim 4 , wherein the system has at least three levels of secondary air ducts for injection of secondary air.  
     
     
         6 . The method of  claim 1 , wherein the velocity of the injected air is such that the ratio of the velocity to the furnace width is between about 3 sec −1  to about 60 sec −1 .  
     
     
         7 . A method for increasing combustion furnace efficiency, comprising: 
 providing a furnace with a plurality of secondary air injection ducts, asymmetrically positioned in an opposing manner;    injecting fuel with primary air through the burners prior to injection secondary air;    injecting secondary air through the plurality of secondary air injection ducts;    wherein the velocity of the injected air is such that the penetration of the injected air is greater than the furnace width by at least about 1.5 widths;    thereby increasing furnace efficiency via mixing and rotation of the combustion space.    
     
     
         8 . The method of  claim 7 , wherein the temperature of the injected air is between about 40 and about 460 degrees centigrade (10-50% redirected combustion air).  
     
     
         9 . The method of  claim 8 , wherein the temperature of the injected air is between about 76 and about 340 degrees centigrade (20-40% redirected combustion air).  
     
     
         10 . The method of  claim 7 , wherein the system has at least two levels of secondary air ducts for injection of secondary air.  
     
     
         11 . The method of  claim 10 , wherein the system has at least three levels of secondary air ducts for injection of secondary air.  
     
     
         12 . A method for increasing combustion furnace efficiency, comprising: 
 providing a furnace with a plurality of secondary air injection ducts, asymmetrically positioned in an opposing manner;    injecting fuel with primary air through the burners prior to injection secondary air;    injecting secondary air through the plurality of secondary air injection ducts;    wherein the velocity of the injected air is such that the combustion zone rotates at least one half revolution prior to exiting the furnace;    thereby increasing furnace efficiency via mixing and rotation of the combustion space.    
     
     
         13 . The method of  claim 12 , wherein the temperature of the injected air is between about 40 and about 460 degrees centigrade (10-50% redirected combustion air).  
     
     
         14 . The method of  claim 13 , wherein the temperature of the injected air is between about 76 and about 340 degrees centigrade (20-40% redirected combustion air).  
     
     
         15 . The method of  claim 12 , wherein the system has at least two levels of secondary air ducts for injection of secondary air.  
     
     
         16 . The method of  claim 15 , wherein the system has at least three levels of secondary air ducts for injection of secondary air.