Drying Characteristics of Powdered Wheat Straw and Its Mathematical Modeling

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The objective of this research was to study the drying characteristics of powderedagricultural residues. Drying experiments of wheat straw (Triticum aestivum) wereconducted at four temperatures of 50, 60, 70, and 80°C by a thermogravimetric analyzer.Drying temperature had a significant effect on the moisture change and drying time.There was no constant drying rate period, but a short rising rate period was evident forall drying process due to increasing temperature of the sample at the beginning of drying.Six mathematical models were selected to describe the drying characteristics of wheatstraw. The goodness of fit was evaluated by the coefficient of determination (R2), thereduced chi-square (c2), and the root mean square error (RMSE). Midilli et al. model wasfound to be the best for modeling the experimental data. The values of effective moisturediffusivity of wheat straw dried at 50, 60, 70, and 80°C were calculated to be 1.13×10-8,1.48×10-8, 1.66×10-8, and 2.29×10-8 m2 s-1, respectively.