Drying Technology
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Date
2013-04-05
Journal Title
Journal ISSN
Volume Title
Publisher
Taylor & Francis
Abstract
A mathematical model for predicting moisture profile in
parboiled paddy during drying was developed using the prolate sphe
roidal coordinate system. The model was solved using the Crank
Nicolson central difference scheme and the variation of its predictive
potential with paddy cultivar was investigated. Parboiled paddy dry
ing was carried out at 60C using a cabinet tray dryer. The variation
of the moisture ratio of different paddy cultivars (Banki, De-gold,
and Liberia) with time and drying rate and with time and moisture
content was determined. Model validation was carried out using
residual plots, root mean square deviation, and coefficient of deter
mination. The parboiled Banki, De-Gold, and Liberia paddy culti
vars had equivalent diameters of 3.73, 4.75, and 3.68mm, prolate
spheroidal geometric dimensions (equatorial and polar radii) of 1.16
and 4.78mm, 1.22 and 5.45mm, and 3.10 and 3.92mm, and effec
tive moisture diffusion coefficient of 2.81934 10 10, 5.71515
10 10, and 3.77336 10 10m2/s, respectively. Drying of parboiled
paddy occurred in the falling rate phase with initial period of induc
tion and critical moisture content that varied with cultivar. The
residual plots showed that the model was acceptable for predicting
moisture transport in all the cultivars during drying. Comparison
of the observed and predicted moisture ratios showed low root mean
square deviation and high coefficient of determination, which varied
with cultivar indicating that the predictive potential of the model
was cultivar dependent.