Experimental and Computational Study of Supercritical Fluid Extraction (SFE) of Omega-3 Components from Fish Oil in Structured Packing

Abstract

The benefits of polyunsaturated fatty acids and their implications for human health have gained scientific attention to their extraction from biological sources, not being produced by the human body. Most known industrial productions of omega-3 fatty acids often work under operating conditions that may degrade these components and they often use toxic or flammable solvents that can adversely affect human health. In this sense, innovative and interesting prospects are provided by Supercritical Fluid Extraction (SFE). In this work, two parallel studies were carried out: an experimental activity in a laboratory apparatus using supercritical carbon dioxide (scCO2) and preliminary computational fluid dynamics (CFD) simulations, limited to the hydrodynamic aspects of the process. In the experimental apparatus a Sulzer® EX structured packing, made up of corrugated metal gauze sheets, was used as the column filler. The study made it possible to identify the optimal operating conditions leading to an enrichment of the starting mixture in Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA), target products. CFD simulations were based on the Volume of Fluid (VOF) approach, suitable to the present complex multiphase system with two phases in close contact (transesterified fish oil and scCO2). The meatus created by the corrugations of the metal gauze was chosen as the calculation domain representative of the system. The computations were performed by the commercial software Ansys Fluent®, which allowed the prediction of the hydrodynamic evolution of the system through transient simulations. CFD predictions were in qualitative agreement with the experimental results.