Estimation of the composition of soybean biodiesel/soybean oil blends from permittivity measurements

Abstract

The relative permittivity of soybean biodiesel/soybean oil blends was determined in the full range of composition, at temperatures between 298K and 343K. Measurements were carried out at frequencies between 1kHzand 100kHz, using a broadband cell. The relative RMS uncertainty of the dielectric measurements was below 1%.For all the studied samples, the relative permittivity decreases with temperature and increases with biodiesel content, in both cases linearly.From the experimental results, a model was developed to estimate the permittivity of the blends as a function of composition and temperature. The RMS uncertainty of the estimation is less than ±0.01. Furthermore, the blend composition was modeled as a function of permittivity and temperature. The RMS uncertainty of theestimation was below 9% for temperatures between 298K and 313K.