Experimental and computational study on the compatibility of biodiesel/diesel/methanol blended fuel

• LLE data containing n-alkane, fatty acid methyl ester and methanol were measured.
• The experimental data were well modeled using NRTL and UNIFAC-Dortmund models.
• The new and reliable model parameters were obtained.
• Phase chart for the diesel/biodiesel/methanol blends was successfully simulated.

In order to obtain the solubility values for the diesel/biodiesel/methanol blends and prepare the homogeneous single blended fuels, biodiesel or diesel was composed approximately of a series of model compounds and the liquid–liquid equilibrium (LLE) data for the seven ternary and one quaternary systems involving in n-alkane, fatty acid methyl ester and methanol have been measured and performed thermodynamic modeling. The experimental data were correlated by NRTL model and UNIFAC-Dortmund model with a good accuracy. The new parameters of NRTL and UNIFAC-Dortmund models were obtained systematically and they were tested to be reliable for the (diesel + biodiesel + methanol) system through the prediction of some experimental and literature data. Meanwhile, the phase chart for the (diesel + biodiesel + methanol) mixture was successfully simulated using Aspen Plus software based on the obtained NRTL and UNIFAC-Dortmund models parameters, which was applied to investigate the compatibility of biodiesel/diesel/methanol blended fuel. In this work, the diesel/biodiesel/methanol blended fuel containing 30% biodiesel is likely to be border-line in terms of homogeneous system.