Thin-layer drying of Raffia textilis fiber

Abstract

The Raffia textilis fiber has interesting specific mechanical properties among other vegetables fibers. But its production remains entirely based on empirical knowledge. The fibers are dried in the open air and in the shade for about 48 hours. This study explores the effect of the drying temperature, from 30° to 70°C, on its drying kinetics. It was found that the drying duration passes from 55 min at 30 °C to 20 min at 70 °C. Among the three models used to simulate the drying kinetics, the Page model yields the best results. The values of the parameters of this model agree with the hypothesis that the water diffusion is one-dimensional. The activation energy of water in the fiber varies from 49 to 71 KJ/mol, depending on the model used. The effective diffusion coefficient is about 3x10-14 m2.s-1 at 30 °C. This low value justifies the traditional use of the raffia leaves for house roofs.

Determination of effective moisture diffusivity and activation energy for drying of powdered peanut shell under isothermal conditions

“…The effective moisture diffusivity (D eff ) and the activation energy (E a ) are the important drying parameters for describing the diffusion mechanism and designing a new dryer (Albitar et al 2011;Chen et al 2011). In the literature, the drying parameters are generally determined under isothermal conditions by a two-step method (Elenga et al 2011;Li and Kobayashi 2005). First, effective moisture diffusivity is calculated from the drying curves by Fick's second law for each of several drying temperatures.…”

“…In recent years, the two-step method has been widely used, and the drying parameters values have been obtained for numerous materials, such as fruits (Minaei et al 2012), food (Doymaz and Kocayigit, 2011), fiber (Elenga et al 2011), vegetables (Wu et al 2007), sawdust (Chen et al 2012), and leaves (Kaya and Aydin 2009). However, few drying studies have been carried out for biomass powder, and the drying parameters of agricultural residues such as peanut shell are unknown.…”