Volumetric and Transport Properties of Commercial Diesel + FAME from Residual Chicken Fat in the Interval of 293.15 to 353.15 K

This study presents the experimental characterization of the volumetric and transport properties of pseudo-binary mixtures of commercial diesel and residual chicken fat methyl ester biodiesel over the temperature range of 293.15–353.15 K at 0.078 MPa. Density measurements were performed using a U-shaped vibrating-tube densimeter; kinematic viscosities were obtained using Cannon–Fenske capillary viscometers. The results show that density decreased with increasing temperature and diesel content. The excess molar volume (VE) was negative for all mixtures; the strongest volumetric contraction took place at around x1 ≈ 0.4–0.6. The Redlich–Kister equation and the Prigogine–Flory–Patterson (PFP) model were applied to represent excess molar volumes, with an absolute average deviation (AAD) lower than 14.92%. The thermal expansion coefficient (αP) and its excess property (αPE) further confirmed the existence of non-ideal mixing driven by polar–apolar interactions. The kinematic viscosity (ν) was confirmed to be temperature-dependent and increased with the amount of FAMEs; this effect can be associated with the greater polarity and structural rigidity of esters. The McAllister model also adequately reproduced the dynamic viscosity (η) with an AAD < 4.2%. Furthermore, an increase in the activation enthalpy (ΔH≠) was observed at higher FAME fractions, indicating a high energy demand is required to overcome the internal energy barrier for the initial displacement of the molecules.