Simulation of supercritical fluid extraction of essential oil from natural products

Abstract

A transport phenomena based model has been used and solved to predict the extraction of essential oils from three different natural materials. This study discusses the extraction of essential oils and the parameters which control the process of mass transfer. The model presented here considers both intra-particle resistance and external film resistance to mass transfer and partial differential equations for unsteady-state mass balance for solute in both solid & supercritical phases are developed based on the concept proposed by Melreles et al. (2009) and solved numerically based on a linear equilibrium relationship. The intra-particle diffusion coefficient and equilibrium constant are used as adjustable parameters for Basil & Rosemary leaves and Vetiver roots respectively. The adjustable parameter is optimized by Golden Section Method and the remaining variables such as density and viscosity are computed using available empirical correlations. The solute concentration in the supercritical carbon dioxide leaving the packed beds of natural products was predicted as a function of extraction time, bed height, solvent flow rate and particle diameter. This model predicts a cumulative yield within an error limit of +6.22% to −0.42% for Rosemary leaves, +3.68% to −3.29% for Basil leaves and +5.93% to −4.73% for Vetiver roots. The our model shows better results as compare to those obtained in the literature. © 2016 Elsevier GmbH