Thin-Layer Drying of Burdock Root in a Convective Dryer: Drying Kinetics and Numerical Simulation

Abstract

This work investigated the thin-layer drying kinetics of Vietnam burdock root in a convective dryer. The thin-layer drying models and mass transfer coefficient were determined by experiment and analysis approach. Furthermore, a numerical simulation was performed to describe the moisture distribution inside the material. The regression models and mathematical equations were determined by Statgraphics software and the EES software. The survey range in this work: 50-70oC air temperature, 1-2 m/s air velocity, 22 ± 5 mm slice diameter, and 5 ± 0.2 mm slice thickness. The results show that the Page model was the best model to describe the drying behavior of burdock root, with the correlation coefficient of R2 > 0.9992; the moisture diffusivity coefficient De = 3.4520 x 10-9-1.8516 x 10-8 m2/s; moisture transfer coefficient hm = 1.3256 x 10-7-7.8375 x 10-7 m/s. Furthermore, the simulation results visualize the moisture distribution inside the burdock root slice in the drying process.