DISCRIMINATION OF THERMODYNAMIC MODELS APPLIED TO SUPERCRITICAL-FLUIDEXTRACTION

Experimental planning associated with model discrimination is a techni que aimed to optimize experimental procedures causing a cost reduction . Surprisingly, this technique has not been used extensively in phase- equilibrium experiments. Although this rationalization may not be so e ffective in vapor-liquid equilibrium at low pressures, the same is not true for systems at high pressures. This is the case when considering supercritical-fluid extraction (SCFE) where molecular asymmetry and t he proximity to the critical point make modeling of such systems a cha llenging task. As it has been pointed out in the literature, the succe ss of SCFE relies on the ability to predict and correlate the correspo nding thermodynamic behavior. The objective of this work is to show th at sequential model discrimination may be used as a rational method fo r obtaining experimental data, even when a simplified methodology is a pplied. Literature data on SCFE of two carbon dioxide containing syste ms were used along with current thermodynamic models. The results show that when model discrimination is applied, less experimental informat ion is required as compared to conventional model selection, without a ny loss of fitting quality.