Modelling and Simulation of a Complete Supercritical Fluid Extraction Plant with Countercurrent Fractionation Column

The most complete dynamic model to date of a supercritical fluid extraction (SFE) plant is presented and experimentally validated. The SFE flowsheet is modularly organized into a set of detailed sub-models of the main unit operations, including the extraction packed column, the supercritical solvent heat exchanger, the product recovery and solvent regeneration column, and the solvent make-up. The modules are interconnected through appropriate boundary conditions that establish continuity of mass, momentum, and energy. The present model significantly improves our previous modeling efforts by, among other features, including the gas compressor unit, extending the operation of the whole plant to nonisothermal conditions, and upgrading the packed column model for reflux mode operation. The SFE model was validated against experimental data for the fractionation of edible oil mixtures by supercritical carbon dioxide. Good agreement was obtained between experimental and predicted results; moreover, the model correctly predicts the trends with different operating and design parameters.