Permittivity of gasoline/methanol blends. Application to blend composition estimation

Abstract

The relative permittivity of gasoline/methanol blends was determined at 100 kHz, in the full range of composi-tion, at temperatures between 296 K and 323 K.From experimental results, permittivity is fitted to a third degree polynomial on methanol content, and, at each composition, the permittivity of blends decreases linearly with temperature.From the analysis of the experimental data, a model is developed to estimate the relative permit-tivity as a function of blend composition and temperature. The model fitting is very satisfactory, with an RMS absolute uncertainty of 0.43. The parameters of the model are determined from experimental data for pure gaso-line and methanol, and were checked by means of a non-linear fitting using all the experimental data, with very good agreement.Another model is proposed to estimate the composition of blends from temperature and permit-tivity measurements. From the comparison to experimental data, the RMS absolute uncertainty of the estimation is below 2%.