Variation of moisture content with respect to the
drying time was determined experimentally and it was
compared with the results of numerical modeling (“Fig. 8,”).
Drying rate of copra can be divided into two sub-drying
periods; first and second falling rate periods [11]. The critical
moisture content at the starting of second falling rate period
was found to be 30% (w/w dry basis). A final moisture level
in copra of 7% (w/w dry basis) was achieved within 20 hours.
The process of model tuning by varying the diffusion
coefficient to comply with experimental data confirmed that
the significant change of moisture diffusion was occurred at
the moisture content of 30% (w/w dry basis). Accordingly, the
diffusion coefficient was found to have two values
representing the first and the second falling rate periods. -
(14).