Relative permittivity of bioethanol, gasoline and blends as a function of temperature and composition

MANDALUNIS, S.; SORICHETTI, P.A.; ROMANO, S.D.

FUEL

ELSEVIER SCI LTD

Año: 2021 vol. 293

0016-2361

The dependence of the real part of the relative permittivity of bioethanol, gasoline, and their blends was determined. Measurements were performed in the temperature range between 298 K and 323 K, at a frequency of 100 kHz. Temperature was stabilized within ±0.1K and the uncertainty in the relative permittivity was ±0.01. In all the studied blends, the real part of the relative permittivity decreases as a function of temperature with a very good fit to a linear function. At each temperature, the real part of the relative permittivity increases with the bioethanol content in the sample. The permittivity as a function of blends composition fits very satisfactorily to a fourth - order polynomial. In all cases, the mean square error (ΔRMS) of the permittivity estimation was less than 0.09. Furthermore, for bioethanol concentrations lower than 25%, a second - order polynomial fits with an ΔRMS error below 0.04. At higher bioethanol concentrations, a linear function fits with an ΔRMS error below 0.13. The bioethanol concentration in the blends is estimated from permittivity and temperature measurements, with a mean square error in the estimation of the composition lower than 0.5% in all cases. This work shows that measurements of electrical properties can be very effective in the characterization of gasoline - ethanol blends for laboratory and industrial applications.