Design, construction, and test program of a 300,000 lb/h steam generating capacity multicell fluidized-bed boiler (MFB), as a pollution free method of burning high-sulfur or highly corrosive coals, is being carried out. The concept involves burning fuels such as coal, in a fluidized-bed of limestone particles that react with the sulfur compounds formed during combustion to reduce air pollution. Nitrogen oxide emissions are also reduced at the lower combustion temperatures. The CaSO/sub 4/ produced in the furnace is discharged with the ash or regenerated to CaO for reuse in the fluidized-bed. Information is presented on: continued operation of the Rivesville MFB steam generating plant in a commercial mode and for determining performance and emission characteristics; studies and tests on fly ash characterization and reinjection, fuel feed educators and needles, air distributor, corrosion--erosion and sulfur capture; engineering studies to improve MFB performance and reliability.