FRAGMENTATION OF LARGE COAL PARTICLES IN A DROP-TUBE FURNACE

The fragmentation of large coal particles (1 6 mm) was studied by introducing them singly into an isothermal drop-tube reactor maintained at 1273-1383 K. Fragmentation due to thermal shock and subsequent cracking during the devolatilization and char combustion stages was observed for all particle sizes. The extent of fragmentation increased with increasing initial particle size and temperature. Particle rotation as a result of ejection of volatiles was also observed, with a frequency of 200-1300 Hz depending on particle size.