While the operational conditions of a fluidized bed are known to influence the fuel axial mixing, the effect of the
resulting axial location of the fuel particles on the char gasification rate remains unexplored. In this work, a
laboratory-scale bubbling fluidized bedwas used to investigate how the gasification rate of biomass charwas influenced
by the fuel axial location (during pyrolysis and char gasification), the pyrolysis atmosphere, the fuel size,
and the fuel concentration. When pyrolysis at the bed surface was followed by char gasification inside the dense
bed the char gasification ratewas up to 2-fold lower than the other combinations of the fuel axial location,which
held similar rates. Cooling the char after pyrolysis decreased the char gasification rate in all cases studied. The gasification
rate increased when the fuel particle size was decreased, and its dependence on the degree of char conversion
was also affected. Thus, the operational conditions of a fluidized bed reactor, through modified fuel axial
mixing, can influence the char gasification rate. Furthermore, experimental determination of reactivity data in
laboratory-scale systems must account for the axial location of the fuel at the desired end-scale, using similar
fuel particle sizes.
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