Assessment of kinetics, effective moisture diffusivity, specific energy consumption, and percentage of thyme oil extracted in a hybrid solar‐electric dryer

Abstract

AbstractThis research deals with the analysis process of thyme in a hybrid (solar‐electric) dryer. The drying process was administered using three air velocities of 1, 1.5, and 2 m/s and four temperatures of 40, 50, 60, 70°C. The drying rate developed with the increase in temperature and air velocity, therefore decreased the drying time. Ten mathematical models were applied to predict the drying kinetics of thyme. Consequently, the best model to describe the drying kinetics of thyme was Midilli model. The values activation energy and effective moisture diffusivity were ranged between 10.9 to 16.33 kJ/mol and 2.172 × 10–10 to 1.23 × 10–10 m2/s, respectively. The oil yield was significantly affected by drying situations. The essential oil of the leaves was determined by hydrodistillation. So, the highest essential oil amount equal to 2.4 CC (vol/wt) was obtained at temperature of 40°C and air velocity of 1.5 m/s.Practical ApplicationsDrying is the most significant process to maintain agricultural crops. The purpose of drying crops is the decrease of the moisture content to a level that provides secure storage over an extended term, and significant influence on the quality of dried crops. In this research, drying kinetics of Thyme at different air velocity and air temperatures in hybrid dryer were studied. Moreover, simplistic models for the simulation of the drying process were offered. Consequently, the aim of this work was to Introducing a new hybrid dryer for herbal plants, to decrease volatile loss or degradation of essential oil extracted from Thyme. It is application in medicinal plants post‐harvest technology.