Development of a 220-MW Coal-Fired Combustion Turbine Combined Cycle: Current Status

In the eight-year, multicontractor program to develop a 220-MW coal-fired combustion turbine combined cycle plant, the team is now into its third year of subscale slagging combustor testing. Because of an ability to accept unbeneficiated, utility-grade coal, the slagging combustor is the key to the direct coal-fired combustion turbine. The projected plant will contain two 80-MW combustion turbines equipped with slagging combustors, two heat recovery steam generators, and a 65-MW steam turbine.In testing to date, the concept has demonstrated its ability to handle high- and low-sulfur bituminous coals, and low-sulfur subbituminous coal. Feeding the fuel in the form of pulverized coal has proven to be superior to coal-water mixture type feed. The program objectives relative to combustion efficiency, combustor exit temperature, NOx emissions, carbon burnout, and slag rejection have been met. Work continues to reduce alkali, particulate, and SOx levels leaving the combustor. Parametric studies have been made that focus on the latter two problems. They indicate that faster, more thorough slag removal between the rich and lean stages is the path toward achieving lower emission of SOx, alkali, and particulates. New components have been added to the subscale combustor for this purpose.Copyright © 1991 by ASME