A shrinking core model for seeds oil extraction with particularization to Camelina oil separation

Abstract

The oil extraction from a spherical particle in an adequate solvent is analyzed by a dynamic model. The oil extraction occurs by moving the unsolubilized solid/solute-free phase interface toward the center of the particle. We assume that the transport of solute molecules has three resistances: (1) the resistance due to oil core dissolving; (2) the resistance due to the solute-free portion of the particle; (3) the resistance due to a surface layer near solid–liquid interface. Generally, the equation governing the dynamic behavior of oil extraction is numerically solved. However, sometimes analytical expressions for the time dynamics of the size of the unsolubilized oil portion can be obtained in some special cases. The present analysis on oil process extraction takes into account the effect of variable bulk solute concentration and of seed internal characteristics such as particle porosity, particle tortuosity and core oil dissolving kinetics. Result consists in a general mathematical model whose particularization is given for the case of Camelina seeds oil extraction. For Camelina seeds the oil hexane extraction has been characterized by particularization of the general modified shrinking core model. It has obtained that the particle dimensionless porosity is set to 0.08, while the constant of kinetic process from the shrinking core surface is strongly dependent on core position and on the temperature after relation kd=kd0(t)(rc/R)n with n=4 and kd0(t) in the range 4.3–8.3 10−8m/s.