An Experimental Study of Wheat Drying in Thin Layer and Mathematical Simulation of a Fixed-Bed Convective Dryer

Abstract

Drying of wheat (Algerian cultivar: Hadba03) in thin layers was studied and mass flux phenomenon was used to characterize the thin-layer drying process. Thin-layer drying of wheat was determined for drying air temperature range of 40–60°C, relative humidity of drying air from 10 to 30%, air velocity of 0.7 m/s, and initial grain moisture from 26 to 31% (dry basis). Equilibrium moisture content of wheat was determined using desorption isotherms obtained from the thin-layer drying data. An equilibrium model for a stationary deep bed with drying air moving vertically upward was developed using mass and energy balance between grain and drying air in the bed and drying air characteristics obtained from thin-layer drying experiments. The developed model was validated by drying wheat in a laboratory dryer using different drying air temperatures and initial moisture contents.

Keywords:

• Convective dryer
• Desorption isotherms
• Kinetic model
• Thin layer
• Wheat

ACKNOWLEDGEMENTS

The authors thank Wahbi Jomaa and Denis Bruneau of the laboratory TREFLE of Bordeaux, France, and Meziane Nasredine of the University of Chlef, Algeria, for their technical assistance during this study. We also thank the laboratory TREFLE of Bordeaux, France, for allowing the lead author to conduct thin-layer experiments. We thank the Canada Research Chairs program for partial financial support.