NEW REGENERABLE SORBENTS FOR FLUIDIZED-BED COAL COMBUSTION

Calcium and barium titanate (CaTiOs and BaTiOa) and calcium aluminate cement have been found to possess properties which make them attractive candidates for use as regenerable sorbents for SO2 in a fluidized bed coal combustion system. In tests using thermogravimetry, each of these solids was considerably more reactive than the conventional sorbents limestone and dolomite. The titanates also appear to be unique in that they completely retain their activity when cycled repeatedly between sulfating and regenerating conditions. Sorbent pellets formed from calcium aluminate cement were extremely strong and, in a test of this cement conducted in a pilot-plant scale fluidized bed coal combustor, the attrition rate was less than l/30th of that experienced with limestone. When fly ash was incorporated into calcium aluminate cement pellets, the sulfation rate was increased nearly threefold relative to pellets prepared without fly ash, indicating an effect which may have been catalytic. © 1979, American Chemical Society. All rights reserved.