Comminution characteristics of Korean anthracite in a CFB reactor☆

Comminution characteristic of Korean anthracite has been determined with operation conditions in a laboratory scale circulating fluidized bed (CFB) combustor. The fragmentation of the anthracite occurs explosively, and generates lots of fine particles at an early stage of devolatilization. The fragmented particles continue to be reduced with generation of the fine particles during an attrition stage in the CFB combustor. With an increase of operation temperature, the coal shows a high degree of fragmentation and generation of fine particles in the CFB reactor. The particle fragmentation occurs actively as its size and Hard Grove Index (HGI) increase. The attrition is also affected with particle size and HGI of the coal. The initial surface crack and the fine clusters on the particle surface are found to be reasons for explosive fragmentation and for generation of fine particles during devolatilization and combustion in the CFB reactor.