From the correlation of binary systems involving supercritical CO2 and fatty acid esters to the prediction of (CO2-fish oils) phase behavior

In this paper, a purely predictive model for the phase equilibria computati on of mixtures involving fatty acid esters (FAE) and supercritical carbon d ioxide is proposed. In a first step, the phase equilibria modeling of FAE/C O2 binary systems were performed using the Peng-Robinson equation of state. To obtain a purely predictive model, the critical properties (T-c, P-c,) a nd the acentric factor (omega) of the FAE were estimated with specific corr elations. Moreover, the group contribution method developed by Abdoul et al ., which allows the prediction of binary interaction parameters (k(ij)), wa s extended to eater compounds and an additional group (the ester function) was defined. Such an approach allowed us to correlate with quite good accur acy all the binary FAE/CO2 systems. In a second step, dew points of (CO2/fi sh oil) systems were measured and the previous model was used to check its capability in predicting these data. The fish oil under study contained 30 different fatty acid ethyl eaters, and the model was able to predict with v ery good accuracy the measured saturation pressures.