Abstract: In order to study the effect of loading on the drying time, drying rate, drying efficiency and unit energy consumption during microwave drying of cotton stalks, the experiment used microwave drying equipment with a microwave frequency of 2 450 MHz and an output of 1 kW. The amount of cotton stalks ranging from 34 to 200 g is dried.
The results show that: the microwave drying equipment is in the deceleration phase after a short speed increase; the dry data is nonlinearly fitted by 7 common thin layer drying models, and the coefficient, root mean square error and dispersion are determined by comparison. Sum of squares, the Midilli model was found to be the optimal model for microwave drying of cotton stalks. The drying coefficient decreased with the increase of loading. When the loading increased from 34 g to 200 g, the drying time increased from 10 min. By 20 min; the effective diffusion coefficient of water in the cotton stalk decreases with the increase of the loading, and the average value is between 1.8078×10-8～4.1997×10-8 m2/s, and the average is obtained based on the Arrhenius equation. The activation energy is 4.82 W/g; when the loading is 34-200 g, the microwave drying efficiency can be improved by increasing the loading (7.52% to 19.78%), and the unit energy consumption of microwave drying (12.49-35.90 MJ/kg) is reduced
microwave drying of cotton stalks
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