THIN-LAYER DRYING AND WETTING OF WHEAT

The research objectives were to determine accurate thin-layer drying a nd wetting equations for 'Katepwa' wheat. Equilibrium moisture content (EMC) equations for adsorption and desorption were also developed bas ed on the experimental drying and wetting data. The modified Chung-Pfo st equation predicted reasonably well the EMC for both adsorption and desorption of wheat. The range of test conditions were: temperature 7. 6-35.1 degrees C; relative humidity 28-92%; air velocity 0.04-0.2 m s( -1); and initial moisture content 9.2-16.7% (wet mass basis). Thin-lay er drying of wheat was affected by air temperature, relative humidity, and initial moisture content while thin-layer wetting also slightly d epended on air velocity. The semi-empirical equation of Page was more accurate than the theoretical diffusion equation with the diffusion co efficient dependent on temperature only.