Methods for operating a furnace

Abstract

A method for operating a furnace, such as, for example, a fluidized bed reactor, includes introducing an alkali-containing material and a hydrous clay into the furnace, the hydrous clay having a moisture content of at least about 5% by weight. The method further includes heating at least a portion of the alkali-containing material and hydrous clay, such that at least a portion of the hydrous clay is at least partially calcined and the at least partially calcined clay adsorbs at least a portion of alkali present in the furnace. The method further includes removing at least a portion of the at least partially calcined clay and adsorbed alkali from the furnace.

1 - 67 . (canceled) 
     
     
         68 . A method for combusting fuel in the presence of an alkali-containing material, the method comprising:
 introducing fuel into a furnace configured to combust the fuel;   introducing hydrous clay having a moisture content of at least about 5% by weight into the furnace; and   heating at least a portion of the fuel and hydrous clay, such that at least a portion of the hydrous clay is at least partially calcined and the at least partially calcined clay adsorbs at least a portion of alkali present in the furnace.   
     
     
         69 . The method of  claim 68 , wherein the hydrous clay has a moisture content ranging from about 5% by weight to about 15% by weight. 
     
     
         70 . The method of  claim 68 , wherein the hydrous clay has a moisture content ranging from about 8% by weight to about 12% by weight. 
     
     
         71 . The method of  claim 68 , wherein the hydrous clay comprises lump clay. 
     
     
         72 . The method of  claim 68 , wherein the hydrous clay comprises clay that has been at least one of shredded and crushed. 
     
     
         73 . The method of  claim 68 , wherein the hydrous clay comprises non-beneficiated clay. 
     
     
         74 . The method of  claim 68 , wherein the hydrous clay comprises kaolinite. 
     
     
         75 . The method of  claim 68 , wherein the hydrous clay comprises ball clay. 
     
     
         76 . The method of  claim 68 , wherein the hydrous clay comprises clay derived from overburden from a kaolin mining operation. 
     
     
         77 . The method of  claim 68 , wherein the hydrous clay has a BET surface area of at least about 9 m 2 /g. 
     
     
         78 . The method of  claim 68 , wherein the hydrous clay has a BET surface area of at least about 15 m 2 /g. 
     
     
         79 . The method of  claim 68 , wherein hydrous clay comprises clay derived from crude clay having a moisture content of at least about 15%. 
     
     
         80 . The method of  claim 68 , further comprising calcium carbonate into the furnace. 
     
     
         81 . The method of  claim 68 , further comprising incorporating the furnace into a fluidized-bed reactor system. 
     
     
         82 . The method of  claim 81 , wherein the fluidized-bed reactor system is a circulating fluidized-bed reactor system. 
     
     
         83 . The method of  claim 68 , wherein the step of heating results in calcining at least a portion of the hydrous clay, and the method further comprises:
 adsorbing at least a portion of alkali in the furnace via the calcined clay; and   removing at least a portion of the calcined clay and adsorbed alkali from the furnace.   
     
     
         84 . The method of  claim 68 , wherein the fuel is coal, petroleum coke, or biofuel, or a combination of any of the foregoing. 
     
     
         85 . The method of  claim 68 , wherein the hydrous clay comprises hydrous clay agglomerates having a size of no more than about 3 inches. 
     
     
         86 . The method of  claim 85 , wherein the hydrous clay agglomerates have a size of no more than about 2 inches. 
     
     
         87 . The method of  claim 86 , wherein the hydrous clay agglomerates have a size of no more than about 1 inch. 
     
     
         88 . A method for combusting fuel in the presence of an alkali-containing material, the method comprising:
 introducing fuel and calcium carbonate into a furnace configured to combust the fuel;   introducing hydrous clay having a moisture content of at least about 5% by weight into the furnace; and   heating at least a portion of the fuel, calcium carbonate, and hydrous clay, such that at least a portion of the hydrous clay is at least partially calcined and the at least partially calcined clay adsorbs at least a portion of alkali present in the furnace.   
     
     
         89 . A method for operating a fluidized-bed reactor, the method comprising:
 introducing an alkali-containing material into a fluidized-bed reactor;   introducing hydrous clay into the fluidized-bed reactor, the hydrous clay having a moisture content of at least about 5% by weight;   heating at least a portion of the alkali-containing material and hydrous clay, such that at least a portion of the hydrous clay is at least partially calcined and the at least partially calcined clay adsorbs at least a portion of alkali present in the fluidized-bed reactor; and   removing at least a portion of the at least partially calcined clay and adsorbed alkali from the fluidized-bed reactor.