Drying Kinetics and Thin Layer Modelling of Clerodendrum Volubile (Marugbo) Leaves

The drying kinetics of Clerodendrum Volubile leaves was investigated at different temperature of 50, 60 and 70⁰C in oven dryer. The weight loss with time was recorded and moisture ratio was computed and fitted into different eleven thin-layer drying models. The result showed that moisture ratio reduces with time for all drying temperatures. The drying rate was observed to increase with temperature peaking at 0.185, 0.117 and 0.059 g H2O/g dry solid.min at 70, 60 and 50⁰C respectively. Drying occurred in falling rate period and no constant rate period was observed. The approximation of diffusion model was observed to give the best fit model for the drying process with highest coefficient of determination (0.9985), lowest sum of square errors (0.0032), reduced chi square (0.00012) and root mean square error (0.0107) occurring at 50 ⁰C. The effective diffusivity for Marugbo drying increases with temperature from 3.65×10-12 to 1.28×10-11 m2/s. The Arrhenius equation also described the temperature dependence of diffusivity with activation energy of 57.74 kJ/mol.