An Application of Forced Air Drying Theory to the Deep Bed Drying of Rough Rice (I)

Abstract

A method of analysing deep bed drying of rough rice was devised combining the drying characteristics of a single rough rice and the forced air drying theory of granular bed presented by previous reserchers such as Van Meel and Toei in the field of chemical engineering.
The results obtained were as follows.
1) The equilibrium moisture content of a single grain of rough rice was expressed by equation (16).
2) When the drying characteristics were approximated to a straight line as oba'd in Fig. 3, the drying constant was expressed by equation (17).
3) The equations (11)-(14) of forced air drying theory could be used for the practical drying analysis with sufficient accuracy.
4) The dimensional equations (21)-(24) derived from the dimensionless equations (11)-(14) provided a easier calculating procedure.
5) In practical situation, the coefficicnt (γ) of effective surface area of bulk was in a range of 0.8-0.85.
6) Calculated results could not explain the delay of drying by latent heat of bulk and the large drying rate of early drying period which appeared when air volume was extremely large.