A sutible model for drying kenitic of wood fiber using halogen moistuer analayzer

Abstract

Drying wood fiber is a complex, dynamic, highly nonlinear, and energy-intensive process involving simultaneous heat and mass transfer. So, the theoretical modeling of wood fiber drying because wood fiber shrinks anisotropically during a drying process is very complicated. The semi-theoretical and empirical thin-layer drying models developed on a laboratory scale are a suitable option for examining the drying kinetics of lignocellulose materials. In this study, drying kinetics of wood fibers were evaluated using 18 semi-empirical models at three temperatures of 105°C, 120°C, and 135°C, utilizing a halogen moisture analyzer. The findings revealed that raising the temperature increased the drying constant while decreasing the drying time of wood fibers. According to drying curves, no constant drying rate was observed and all the drying process occurred in two falling drying rate periods. More specifically, despite the high initial moisture content of wood fiber about 170% (based on dry weight), the wood fiber drying process was mainly controlled by diffusion mechanism. The fitness of drying curves on semi-theoretical and empirical models based on statistical parameters, including root mean square error (RMSE), sum of square errors (SSE), and coefficient of determination (R2) showed that the Midilli et al. model had the highest coefficient of determination and the lowest error percentage. Also, the moisture content was more accurately predicted by ANN model than the Midilli et al. model.