DEVOLATILIZATION OF LARGE COAL PARTICLES AT HIGH-PRESSURE

Devolatilization times of large (0.1 and 0.2 g) Utah hvBb and North Da kota lignite coal particles, in the range 15-30s, were measured in air at 101 and 507kPa, at air temperatures of 900 and 1200K in a convecti ve flow reactor. Visual observations indicated infrequent heterogeneou s ignition of the lignite prior to devolatilization and occasional exp losion of bituminous coal particles during devolatilization. Devolatil ization times were correlated with temperature, pressure and particle size. Power-law exponents for tests at 101kPa and 900K were determined to be 2.5 for Utah hvBb coal and 2.2 for North Dakota lignite. At 507 kPa and 900K, exponents decreased to 1.6 for both Utah and North Dakot a coals. At 101kPa and 1200K, exponents were 1.9 for Utah coal and 1.6 for North Dakota lignite. Copyright (C) 1996 Elsevier Science Ltd.