Data, analysis and modeling of physical properties for process designof systems involving lipids

Pure component and mixture properties are necessary for synthesis, design, and analysis of processes forthe production of edible oils, fats, biodiesel, and other lipids. The lack of measured data for these systemsmakes it necessary to develop reliable predictive models based on limited data. We have systematicallycollected data for vapor–liquid equilibrium (VLE), solid–liquid equilibrium (SLE) and related pure com-ponent properties involving lipid systems as a first step toward developing relevant property models.The established consistency tests to evaluate the VLE data of lipid systems as well as lipid properties arebriefly reviewed.

For SLE systems, where consistency tests based on the Gibbs–Duhem equation cannotbe implemented, a consistency test has been developed. It involves limiting conditions and regressionof the parameters for a new thermodynamic model that combines solute activity coefficients in the liq-uid phase at infinite dilution and a theoretically based term to account for the non-ideality in dilutesolutions.

This model gives noticeably better descriptions of experimental data in lipid systems than dotraditional models. Examination of various objective functions for regressing model parameters showedthat some variation of parameter values and differences in accuracy can be found, though they are notlarge.

Some original UNIFAC group contribution parameters for lipids have been revised by fitting to thelipid database.