Primary Fragmentation Behavior of Indian Coals and Biomass during Chemical Looping Combustion

Abstract

Devolatilization and fragmentation are important physical phenomena occurring during solid fuel chemical looping combustion (CLC). Primary fragmentation during devolatilization strongly affects the rate of fuel conversion, emissions, and fine particulates generation in a fuel reactor of a fluidized bed CLC unit, thus forming a critical design input. The present study focuses on investigating the primary fragmentation behavior of large coal and biomass (wood) particles during the devolatilization phase of CLC. Three types of coals (two Indian coals, one Indonesian coal) and one type of Casuarina wood of three sizes in the range of 8–25 mm, at different fuel reactor bed temperatures (800, 875, and 950 °C) are studied for primary fragmentation. Iron ore with 64% Fe is used as the oxygen carrier bed material, with steam as the fluidizing medium in the fuel reactor. The fragmentation behavior is expressed in terms of the number of fragments, fragmentation index, frequency of fragmentation, and particle size di...