Model of Supercritical Fluid Extraction of Vegetable Oil in a Two-Component Approximation

This paper presents a model of supercritical fluid extraction of plant triacylglycerides from seeds of high-oil raw material. Oil is considered in a two-component approximation. A three-component solution with CO₂ is described within the framework of the theory of regular solutions. The sign of the interaction energy of the molecules of the oil components makes it possible to distinguish between two thermodynamic equilibrium modes. Mass transfer through the transport channels of an individual particle is described within the framework of the shrinking core model. Constitutive relations between diffusion fluxes and gradients of chemical potentials are formulated within the framework of the Maxwell–Stefan approach. Each component of the oil has its own front and a pair of shrinking core/transport zone. It is shown that the concentration profiles of the oil components are determined not only by diffusion processes, as is typical in the framework of the one-component approximation, but also by the material two-phase equilibrium of individual components.