20-Atmosphere Rig PFBC Results: Tests 18 and 19. Further Investigation into Agglomerate Formation when Using Limestone as the Sorbent

摘要

In previous tests with Pittsburgh No. 8 coal and Carbon limestone, it was found that the bed began to agglomerate when operating at 10 to 16 atm pressure, 1560 eF bed temperature and 3ft/s fluidising velocity. The problem could only be overcome by increasing the fluidising velocity and/or decreasing the bed temperature. Similar problems have occurred with another coal and limestone in the 20 atm rig (not part of the DOE programme) and are also known to have occurred with coal and limestone in at least one other combustor. The problem did not exist with limestone and a coal having a refractory ash, nor does it exist at the above operating conditions when burning Pittsburg No. 8 and dolomite. Tests 18 and 19 were devised to try and overcome this agglomerating problem by reducing the peak temperatures in the region near the coal inlet nozzle. In Test 18, the intention was to convey the crushed coal into the combustor in a stream of nitrogen, instead of air. In Test 19, the coal was fed as a coal-water slurry. (ERA citation 10:003079)