sand. The sand as additional bed material
is fed into combustion chamber during start-up of the boiler and
when a coal with low ash content is fired or co-fired with other fuel
(i.e. biomass). The behavior and the particle size distribution of granular
materials are very difficult to predict in the circulating fluidized bed due
to a vigorous movement of particles. A number of population balances
in CFB boilers which consider some important fluid dynamic processes
[9–11], such as attrition, fragmentation, segregation, particle shrinking,
char combustion, and heat transfer [12–14] are presented in the literature.
Another key parameter which is very important in the mass
balance is the stress history of particles [15]. In order to map all parameters
mentioned above in the mass balance model, the CFB furnace
chamber is considered for two flow regimes separately