Thermal Properties of Biodiesel and Their Corresponding Precursor Vegetable Oils Obtained by Photopyroelectric Methodology

摘要

The photopyroelectric technique (PPE) was used for thermal characterization of biodiesel and their corresponding precursor vegetable oils. Different configurations of PPE were applied in these studies. The standard and inverse configurations allowed the determination of the thermal diffusivity (α) and thermal effusivity (e), respectively. From these two parameters the thermal conductivity was calculated. Measurements were performed for reference samples (water and ethylene glycol), biodiesel, and some corresponding precursor vegetable oils. The experiments showed good reproducibility, with uncertainties around 1 % to 2 % for all the samples. Lower values for both α and e of the biodiesel when compared to their corresponding precursor vegetable oils were observed, indicating that these thermophysical properties were sensitive to structural changes during the transesterification process.