A series of tests is being carried out in a lft x lft pressurized fluidized-bed combustor. This report presents results obtained in Test 11 when the combustor was operated at 10 and 16 atm, 3 and 4-1/2 ft/s fluidizing velocity and 1560/sup 0/F bed temperature. The feedstock was comprised of Pittsburgh No. 8 coal and Plum Run dolomite. The main objective was to measure the performance when operating with two different coal size distributions - 1/8 inch x 1/16 inch and 1/16 inch x 0. Data on combustion efficiency, sulphur retention, NO/sub x/ emissions, alkali distributions and heat transfer are presented.