The
paper presents a comparison between experimental and model
results of primary fragmentation of a lignite coal in a fluidized
bed (FB). In the experiments, the char particle size distribution
and the general indicators of primary fragmentation (intensity and
index) were determined. The same parameters were calculated using
a mathematical model of the process, fed by data of the fuel (the
amount of volatiles and fixed carbon), fluidized bed temperature,
and inlet particle size distribution. The size distribution and number
of the char particles in fluidized bed significantly differ from the
size distribution and number of inlet coal particles. Char population
has a bimodal distributionseparate distributions for the smaller
and larger sets of fragments. The experimental and model results show
the same tendency: a coal particle partially breaks at the beginning
of devolatilization, giving a large number of fine fragments, while,
as the process continues, the rest of the parent particle sometimes
breaks down into a smaller number of larger pieces, and sometimes
does not fragment at all. Review of the Weibull distribution coefficients
enables prediction of the char particle size distribution for the
characteristic fluidized bed conditions and inlet coal particle sizes.