Integration of oxy-fuel and air-fuel combustion

Abstract

A furnace is heated by a burner that can be selectively operated by either air-fuel or oxy-fuel combustion. The burner comprises a conduit for fuel, a conduit for air, a conduit for oxidant, and control means for regulating flow through the air and oxidant conduits. An air-fuel fired furnace can be modified by addition of the oxidant and fuel conduits and the control means for regulating flow through air and oxidant conduits.

1 . Combustion apparatus comprising
 (a) a furnace enclosing a combustion zone and having at least one burner through a wall of the furnace to which air is fed through an air conduit and fuel is fed through a burner fuel conduit from outside the furnace to be combusted at the burner within the combustion zone;   (b) an oxidant conduit through which oxidant can be fed into the furnace from outside the furnace; and   (c) control means that regulates the flow of oxidant through the oxidant conduit and the flow of air through the air conduit such that the ratio of air flow to oxidant flow can be controlled;   wherein the oxidant conduit and the burner fuel conduit are oriented with respect to each other so that the oxidant conduit feeds oxidant into an oxidant mixing zone in the combustion zone and the burner fuel conduit feeds fuel into a fuel reaction zone in the combustion zone which is segregated from the oxidant mixing zone.   
   
   
       2 . Combustion apparatus according to  claim 1  wherein the oxidant conduit feeds oxidant into the furnace from within the burner. 
   
   
       3 . Combustion apparatus according to  claim 1  wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner. 
   
   
       4 . Combustion apparatus according to  claim 1  further comprising a second fuel conduit through which fuel is fed from outside the furnace to be combusted within the combustion zone. 
   
   
       5 . Combustion apparatus according to  claim 4  wherein the oxidant conduit feeds oxidant into the furnace from within the burner. 
   
   
       6 . Combustion apparatus according to  claim 5  wherein the second fuel conduit feeds fuel into the furnace from within the burner. 
   
   
       7 . Combustion apparatus according to  claim 5  wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner. 
   
   
       8 . Combustion apparatus according to  claim 4  wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner. 
   
   
       9 . Combustion apparatus according to  claim 8  wherein the second fuel conduit feeds fuel into the furnace from within the burner. 
   
   
       10 . Combustion apparatus according to  claim 8  wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner. 
   
   
       11 . Burner apparatus comprising
 (a) a burner to which air is fed through an air conduit and fuel is fed through a burner fuel conduit to be combusted in a combustion zone at the burner;   (b) an oxidant conduit through which oxidant can be fed to the burner; and   (c) control means that regulates the flow of oxidant through the oxidant conduit and the flow of air through the air conduit such that the ratio of air flow to oxidant flow can be controlled;   wherein the oxidant conduit and the burner fuel conduit are oriented with respect to each other so that the oxidant conduit feeds oxidant into an oxidant mixing zone in the combustion zone and the burner fuel conduit feeds fuel into a fuel reaction zone in the combustion zone which is segregated from the oxidant mixing zone.   
   
   
       12 . Burner apparatus according to  claim 1   1  wherein the oxidant conduit feeds oxidant into the furnace from within the burner. 
   
   
       13 . Burner apparatus according to  claim 11  wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner. 
   
   
       14 . Burner apparatus according to  claim 11  further comprising a second fuel conduit through which fuel is fed to be combusted at the burner. 
   
   
       15 . Burner apparatus according to  claim 14  wherein the oxidant conduit feeds oxidant into the furnace from within the burner. 
   
   
       16 . Burner apparatus according to  claim 15  wherein the second fuel conduit feeds fuel into the furnace from within the burner. 
   
   
       17 . Burner apparatus according to  claim 15  wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner. 
   
   
       18 . Burner apparatus according to  claim 14  wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner. 
   
   
       19 . Burner apparatus according to  claim 18  wherein the second fuel conduit feeds fuel into the furnace from within the burner. 
   
   
       20 . Burner apparatus according to  claim 18  wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner. 
   
   
       21 . A method for retrofitting an air-fired furnace, comprising
 (a) providing a furnace enclosing a combustion zone and having at least one burner through a wall of the furnace to which air is fed through an air conduit and fuel is fed through a burner fuel conduit from outside the furnace to be combusted at the burner within the combustion zone;   (b) providing an oxidant conduit through which oxidant can be fed into the furnace from outside the furnace;   (c) providing control means that regulates the flow of oxidant through the oxidant conduit and the flow of air through the air conduit such that the ratio of air flow to oxidant flow can be controlled; and   (d) orienting the oxidant conduit with respect to the burner fuel conduit so that the oxidant conduit feeds oxidant into an oxidant mixing zone in the combustion zone and the burner fuel conduit feeds fuel into a fuel reaction zone in the combustion zone which is segregated from the oxidant mixing zone.   
   
   
       22 . A method according to  claim 21  wherein the oxidant conduit feeds oxidant into the furnace from within the burner. 
   
   
       23 . A method according to  claim 21  wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner. 
   
   
       24 . A method for retrofitting an air-fired furnace, comprising
 (a) providing a furnace enclosing a combustion zone and having at least one burner through a wall of the furnace to which air is fed through an air conduit and fuel is fed through a burner fuel conduit from outside the furnace to be combusted at the burner within the combustion zone;   (b) providing an oxidant conduit through which oxidant can be fed into the furnace from outside the furnace;   (c) providing control means that regulates the flow of oxidant through the oxidant conduit and the flow of air through the air conduit such that the ratio of air flow to oxidant flow can be controlled;   (d) providing a second fuel conduit through which fuel is fed from outside the furnace to be combusted within the combustion zone, and   (e) orienting the oxidant conduit with respect to at least one of the burner fuel conduit and the second fuel conduit so that the oxidant conduit feeds oxidant into an oxidant mixing zone in the combustion zone and said fuel conduit feeds fuel into a fuel reaction zone in the combustion zone which is segregated from the oxidant mixing zone.   
   
   
       25 . A method according to  claim 24  wherein the oxidant conduit feeds oxidant into the furnace from within the burner. 
   
   
       26 . A method according to  claim 25  wherein the second fuel conduit feeds fuel into the furnace from within the burner. 
   
   
       27 . A method according to  claim 25  wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner. 
   
   
       28 . A method according to  claim 24  wherein the oxidant conduit feeds oxidant into the furnace from an opening that is not within a burner. 
   
   
       29 . A method according to  claim 28  wherein the second fuel conduit feeds fuel into the furnace from within the burner. 
   
   
       30 . A method according to  claim 28  wherein the second fuel conduit feeds fuel into the furnace from an opening that is not within a burner.