Method of combusting sulfur-containing fuel

Abstract

A method of combusting sulfur-containing fuel in a circulating fluidized bed boiler includes the steps of (a) feeding sulfur-containing fuel into a furnace of the circulating fluidized bed boiler, (b) combusting the fuel with oxidant gas consisting essentially of pure oxygen and circulated exhaust gas, so as to form exhaust gas having carbon dioxide and water as its main components, and (c) feeding calcium carbonate containing material into the furnace so as to capture sulfur dioxide into calcium sulfate in the furnace. The temperature in the furnace is maintained above 870° C.

1 . A method of combusting sulfur-containing fuel in a circulating fluidized bed boiler, the method comprising the steps of:
 (a) feeding sulfur-containing fuel into a furnace of the circulating fluidized bed boiler;   (b) combusting the fuel with oxidant gas consisting essentially of pure oxygen and circulated exhaust gas, so as to form exhaust gas having carbon dioxide and water as its main components; and   (c) feeding calcium carbonate containing material into the furnace so as to capture sulfur dioxide into calcium sulfate in the furnace,   wherein the temperature in the furnace is maintained above 870° C.   
     
     
         2 . A method according to  claim 1 , wherein the temperature in the furnace is maintained above 900° C. 
     
     
         3 . A method according to  claim 1 , wherein the temperature in the furnace is maintained above 930° C. 
     
     
         4 . A method according to  claim 3 , wherein the circulating fluidized bed boiler generates steam at a temperature of at least about 650° C. 
     
     
         5 . A method according to  claim 4 , wherein the circulating fluidized bed boiler generates steam at a temperature of at least about 700° C. 
     
     
         6 . A method according to  claim 1 , wherein the sulfur-containing fuel is bituminous coal. 
     
     
         7 . A method according to  claim 1 , wherein the oxygen content of the oxidant gas is at least about 21%. 
     
     
         8 . A method according to  claim 5 , wherein the oxygen content of the oxidant gas is from about 21% to about 28%. 
     
     
         9 . A method according to  claim 5 , wherein the oxygen content of the oxidant gas is at least about 28%. 
     
     
         10 . A method according to  claim 7 , wherein the oxygen content of the oxidant gas is from about 28% to about 40%. 
     
     
         11 . A method according to  claim 1 , wherein the average carbon dioxide content in the furnace is about 70%. 
     
     
         12 . A method according to  claim 1 , wherein the average carbon dioxide content in the furnace is from about 50% to about 70%. 
     
     
         13 . A method according to  claim 1 , wherein the average carbon dioxide content in the furnace is from about 70% to about 80%. 
     
     
         14 . A method according to  claim 2 , wherein the sulfur-containing fuel is bituminous coal. 
     
     
         15 . A method according to  claim 3 , wherein the sulfur-containing fuel is bituminous coal.