Abstract:
Centrifugal separator is widely used in cassava starch production for separating starch
from liquid. A hydrocyclone can be used as an alternative for the separation process.
Previous researches observed that starch separation efficiency by a single hydrocyclone
could be improved. Thus, the aim of this research was to study the effects of pressure
and feed concentration in the cassava starch separation process using hydrocyclones
with overflow connected in series. Two hydrocyclones with diameters of 2.8 and 2.2
cm. (referred to Patarasakul et al., 2002) were used. The pressure drop across the two
hydrocyclones in series and the feed starch concentration were varied at 7, 8,9, 10, and
11 bar; and 3, 7, and 11 percent by weight, respectively. The separation efficiencies of
the hydrocyclones in series were calculated using influent and effluent starch slurry
concentration and flow rate to obtain percentage of recovery (%R), percentage of split
(%S), percentage of reduced efficiency (%E'), and cut size (Dso)' Experimental results
showed that %R increased from 72% to 98%, and %E' increased from 68% to 96%
once a single hydrocyclone was replaced by the two hydrocyclones in series. However,
the effluent starch concentration of the two hydrocyclones in series was lower than that
of a single one. In addition, two affecting factors, i.e. the pressure drop across the two
hydrocyclones in series and the feed starch concentration, had insignificant influences
on the separation efficiency of hydrocyclones in series.