Experimental Study of the Operating Parameters Affecting Deep-bed Drying Kinetics of Rough Rice and Comparing with a Non-equilibrium Mathematical Model

Mehdi Torki Harchegani, Ahmad Moheb, Morteza Sadeghi, Mojtaba Tohidi, Zahra Naghavi


A non-equilibrium model for the numerical simulation of rough rice drying in a deep-bed dryer was evaluated for predicting the variation of average grain moisture content with time. For this purpose, a laboratory scale deep-bed dryer was designed and built and the average moisture content of the bed was experimentally determined during the drying process. During the experiments the effects of temperature, velocity, and relative humidity of the drying air on the average grain moisture content, were investigated. Relative error and mean relative error were calculated for the simulation results, and found to be in acceptable ranges (10-15%, and <10%, respectively). Results revealed that the temperature of drying air was the most influential parameter on the drying time. As a final result, the model proved to be able to predict the variation of the average moisture content with time with a good degree of accuracy.


Deep-bed dryer; drying kinetics; mathematical modeling; non-equilibrium; rough rice.

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