Fig. 7A shows the product ash versus the fluidization wash
water flux for both a relatively low and a high gas flux. The same
data are presented in Fig. 7B versus the ratio of the wash water flux
to gas flux. This ratio is indicative of the bubble washing achieved.
It is evident that there is strong continuity in the data, and hence
the results obtained are governed strongly by the precise conditions
applied. The conditions close to the knee of the Tree Flotation
Curve correspond to a low wash water flux to gas flux ratio. Fig. 8
shows the combustible recovery versus the ratio of the wash water
flux to gas flux. Here there is much more scatter, reflecting the
steep nature of the combustible recovery versus the product ash
%, and the selective stripping of particles under different levels of
fluidization water. In general, for a given level of fluidization water,
combustible recovery was found to be improved across all size
fractions when employing the higher gas flux of 2.6 cm/s.