A review of fluidized-bed combustion technology in the United States

Abstract

Work on fluidized-bed combustion (FBC) began in the United States in the mid-1960s, with primary emphasis on industrial applications. With the passage of the Clean Air Act in 1970, the environmental benefits of the technology soon attracted interest. This provided the impetus for expanded effort focused on the reduced nitrogen oxides (NO x ) emissions resulting from lower combustion temperature and sulfur dioxide (SO 2) capture by means of chemical reaction with limestone or dolomite in the fluidized bed. The oil embargo of 1973 further stimulated interest in FBC technology. Recent interest in fuel flexibility has sustained the interest in FBC in the United States. Several U.S. manufacturers now offer atmospheric fluidized-bed combustion (AFBC) and circulating fluidized-bed combustion (CFBC) units for industrial applications. However, FBC for electric power generation remains in the development and demonstration phase. The Tennessee Valley Authority (TVA) and the Electric Power Research Institute (EPRI) are operating a 20-MW(e) AFBC utility pilot plant and are proceeding with plans for a 160-MW(e) demonstration plant with other participants. Research on pressurized fluidized-bed combustion (PFBC) has been under way at Grimethorpe in South Yorkshire, England, at the Curtiss-Wright Pilot Plant in the United States, and at other smaller test facilities. An emerging turbo-charged PFBC concept is likely to stimulate more near-term interest in PFBC technology for both industrial and utility applications. This paper describes the major U.S. programs and test facilities. The remaining technical uncertainties and the future outlook for the technology are also discussed.