Fragmentation on batches of coke or char particles during fluidized bed combustion

During experiments being carried out on the study of batch combustion of coke or char particles in fluidized beds the evolution of the overall combustion resistance with time usually shows an apparent increase of the overall reactivity as combustion develops. This results in the reduction on the obtained value for the overall combustion resistance below what was theoretically expected.One possible explanation for such behavior is that there is some fragmentation of the particles being thrown into the bed, leading to an increase of the external superficial area available for reaction. The augmentation of the external area increases the overall reaction rate which is erroneously interpreted as a reactivity increase of the material of the particles.The subsequent analysis is an evaluation of the influence of particle fragmentation on the combustion rate of batches of solid particles, when such fragmentation is unknown during the analysis of the experimental data.