A program was initiated in early 1980 at the Morgantown Energy Technology Center, Department of Energy, to evaluate the sulfur retention capability of a number of chemically improved limestones. These synthetic sorbents were developed by the University of Tennessee under an agreement with the Tennessee Valley Authority. Fredonia limestone and Shawnee hopper ash, in combination with a binder, are the main ingredients of the artificial sorbents. The manufacturing process of these pellets is described elsewhere. The effectiveness of the sorbents in sulfur emission controls and their calcium utilization potential were originally controlled by a rapid TG method displayed by the University of Tennessee. Performance data in real fluidizing combustion processes were missing. In a cooperative effort between the Morgantown Energy Technology Center and the Energy Research Division of TVA, an agreement was reached to test four new sorbents, a power station fly ash, and Fredonia limestone at the Morgantown 6-Inch Diameter AFBC Facility. The results generated in the fluidized-combustion test confirmed the findings by the University of Tennessee and the test program was determined to be highly successful. Details of the program as well as the results are presented in this report.