Abstract:
The objective of this research was to study the dry
ing characteristics of powdered
agricultural residues. Drying experiments of wheat
straw (
Triticum aestivum
) were
conducted at four temperatures of 50, 60, 70, and 8
0°C by a thermogravimetric analyzer.
Drying temperature had a significant effect on the
moisture change and drying time.
There was no constant drying rate period, but a sho
rt rising rate period was evident for
all drying process due to increasing temperature of
the sample at the beginning of drying.
Six mathematical models were selected to describe t
he drying characteristics of wheat
straw. The goodness of fit was evaluated by the coe
fficient of determination (R
2
), the
reduced chi-square (
χ
χχ
χ
2
), and the root mean square error (RMSE). Midilli
et al.
model was
found to be the best for modeling the experimental
data. The values of effective moisture
diffusivity of wheat straw dried at 50, 60, 70, and
80°C were calculated to be 1.13
×
××
×
10
-8
,
1.48
×
××
×
10
-8
, 1.66
×
××
×
10
-8
, and 2.29
×
××
×
10
-8
m
2
s
-1
, respectively.
Keywords:
Biomass, Effective moisture diffusivity, Isotherma
l condition, Midilli model,
Thermogravimetric analysis.
