Mathematical model of supercritical extraction applied to oil seed extraction by CO2+saturated alcohol — I. Desorption model

摘要: Abstract Supercritical fluid extraction of sunflower seed oil with carbon dioxide was performed in a pilot plant at 30.0 MPa and 40°C, using different amounts methanol, ethanol, butanol hexanol as cosolvent. Extraction process is represented by plotting cumulated vs. time (extraction curve). curve's shape sigmoidal, an inflexion point delay time. Taking into account this behavior desorption model considered to discuss process. Desorption considers fixed bed extractor distributed model. Balance equations computes extracted varying on time, axial radial direction (axial dispersion); considering surface equilibrium mass transfer between bulk fluid. In order adjust experimental data simplified two adjustable parameters, i.e. coefficient parameter. Mathematical resolution requires discretization method, such orthogonal collocation or finite differences. However, if linear considered, more simple semi-analytical solution Laplace Transform also available. Parameter fit done Simplex method minimize sum square errors which the selected choice. Fitting error 3–5%.