This paper presents a new model to
predict the density of biodiesel
+ petrodiesel mixtures at high pressure and high temperature (HPHT)
based on the Murnaghan equation of state, as a function of temperature,
pressure, volumetric composition, and petrodiesel and biodiesel densities.
This model was validated by using experimental data from the literature,
along with a new experimental data set for biodiesel (grape seed,
corn, and linseed) + petrodiesel, at high pressure (0.10–100.00
MPa) and high temperature (293.15–413.15 K) in a composition
range of 0, 20, 40, 60, 80, and 100%vol. These experimental data were
correlated by using the Tammann–Tait equation. From these data,
the following derivative properties were determined: isothermal compressibility
(κT), isobaric thermal expansibility (αP), internal pressure (p
int), and
the difference between pressure and volume heat capacities (c
p – c
v).
Deviations obtained from the model proposed in this work (%AARD) were
less than 0.50% for biodiesel + petrodiesel density data.