Estimation of diffusion parameters in fluidized bed drying

The present work is an attempt to assess the drying kinetics of green pepper in a fluidized bed in a temperature range of 65-105 degrees C. The drying kinetics is modeled using several semi empirical models to estimate the kinetic parameters. Although the semi empirical model could fit the experimental data well within acceptable experimental error limits, the two parameter models such as Henderson Pabis model and Page Model are identified to predict the drying kinetics with lesser error. The kinetic parameter (k) is found to increase with the temperature for all the models. The activation energy (E) estimated using Arrhenius equation is found to be 30.3 kJ/mol, while the Arrhenius constant (k(o)) is found to be 0.09 s(-1). The effective diffusivity coefficient is evaluated using Fick's diffusion equation which is found increase with increase in temperature of the heating medium and to vary from 1.95 x 10(-11) to 7 x 10(-11) m(2)/S. (C) 2009 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.