Liquid-Liquid-Supercritical Fluid Modeling For Systems Containing Carbon Dioxide, Propane And Triglycerides

P. HEGEL; G. MABE; M. ZABALOY; S. PEREDA; E.A.BRIGNOLE

Barcelona, Spain

Congreso; 11th European Meeting on Supercritical Fluids. May 4 ? 7, 2008.; 2008

International Society for the Advancement of Supercritical Fluids (I.S.A.S.F)

The use of mixed near critical solvents (CO2 + propane) for vegetable oil extraction process presents the advantage of the good solvent capacity of propane together with a non-flamable vapor phase due to the CO2 content. With the aim to design and optimize this process, in a previous work, we obtained vapor-liquid-liquid experimental data for the system CO2 + propane + sunflower oil [1]. The modeling of phase equilibria of this near critical solvents with triglycerides using the GCA-EOS model has been studied in several works [3,4], however this model is not able to correctly predict, using the available group binary interaction parameters, the liquid ? liquid ? vapor region for mixtures of carbon dioxide and propane with triglycerides. In this work, we present new experimental phase equilibria data on the binary and ternary systems including CO2, propane and triacetin, which will be useful to correctly asses the interaction parameters of CO2 and propane with the triester group (TG) of the oil molecule. Liquid CO2 is completely miscible with triacetin and the addition of propane increases the liquid immiscibility of this ternary mixture, this is the opposite behavior presented by mixtures with long chain triglycerides, in which the addition of CO2 increases the liquid immiscibility.