SIMULTANEOUS DRYING AND PYROLYSIS OF SOLID-FUEL PARTICLES

Drying and devolatilization are studied at combustion temperatures. Th e surface temperature of particles at the end of drying can significan tly exceed the temperature when devolatilization starts, implying that drying and pyrolysis may partly overlap. Devolatilization is controll ed by heat transfer, when the particle size is large. The critical par ticle size at which heat transfer dominates chemical kinetics is discu ssed. A model for calculating the intrinsic rate of generation of vola tiles in the regime of heat transfer control is presented. A novel iso therm migration method is used for the computation of simultaneous dry ing and pyrolysis inside a fuel particle. It applies to the study of h eat transfer in a one-dimensional geometry with moving phase-change bo undaries, internal fluid now and mass generation, including steep temp erature and density profiles, as frequently encountered in combustion.