Cyclone furnace for oxygen fired boilers with flue gas recirculation

Abstract

A cyclone furnace and method uses a cyclone burner having a cyclone barrel with a re-entrant throat connected to a main furnace for passing combustion products including flue gas that is rich in carbon dioxide. Crushed coal and oxygen are supplied the cyclone burner and at least some of the flue gas from the main furnace is recirculated to the cyclone barrel.

1 . A cyclone furnace comprising: 
 a cyclone burner having a cyclone barrel with a re-entrant throat;    a main furnace connected to the re-entrant throat for passing combustion products from the re-entrant throat to and along the main furnace, the combustion products including flue gas that is rich in carbon dioxide;    crushed solid fuel supply means connected to the cyclone barrel for supplying fuel to the cyclone burner;    oxygen supply means connected to the cyclone barrel for supplying oxygen that is substantially free of nitrogen to the cyclone burner; and    means for recirculating at least some of the flue gas from the main furnace to the cyclone barrel.    
     
     
         2 . A cyclone furnace according to  claim 1 , including means for supplying primary, secondary and tertiary flue gas to the cyclone furnace, at least one of the primary, secondary and tertiary flue gas supply means forming the oxygen supply means.  
     
     
         3 . A cyclone furnace according to  claim 1 , wherein the crushed solid fuel supply means comprise means for supplying crushed coal to the cyclone furnace.  
     
     
         4 . A method of operating a cyclone furnace having a cyclone burner with a cyclone barrel and a re-entrant throat, and a main furnace connected to the re-entrant throat, the method comprising: 
 supplying crushed solid fuel to the cyclone barrel;    supplying oxygen that is substantially free of nitrogen to the cyclone barrel;    igniting the oxygen and crushed fuel in the cyclone burner for creating combustion products that are passed to and along the main furnace, the combustion products including flue gas that is rich in carbon dioxide; and recirculating at least some of the flue gas from the main furnace to the cyclone barrel.    
     
     
         5 . A method according to  claim 4 , including supplying primary, secondary and tertiary flue gas to the cyclone furnace, wherein at least one of the primary, secondary and tertiary flue gas is enriched with oxygen.  
     
     
         6 . A method according to  claim 4 , including supplying crushed coal as the crushed solid fuel.