Predicting the effect of pressure on biodiesel density at pressures of up to 200 MPa based on fatty acid alkyl ester profiles and density values at atmospheric pressure

The purpose of the current study is to propose a procedure to predict the effect of pressure on biodiesel density based on fatty acid alkyl ester profiles and density values at atmospheric pressure. Based on a Murnaghan equation of state to describe the effects of pressure on density and a group-contribution method to factor in the diversity of fatty acid alkyl ester components in biodiesels, the method is applicable up to 200 MPa in a wide temperature range from 280 to 400 K. Comparison of results with experimental data show that the method provides reliable high pressure predictions for biodiesels and biodiesel blends. Typical deviations calculated between the proposed method and experimental data are 0.05% for Fatty Acid Methyl Esters and 0.04% for Fatty Acid Ethyl Esters in terms of Average Absolute Deviation, with maximum deviations of the same order of magnitude as those of experimental uncertainties.