Characterization of renewable diesel, petroleum diesel and renewable diesel/biodiesel/petroleum diesel blends

Abstract

The physicochemical properties of a renewable diesel (RD) and several petroleum diesel (PD)–dominant diesels were examined to assess the feasibility of identifying and quantifying the presence of RD and biodiesel from PD and their blends. Relative to all PD-dominant diesels, the RD exhibited a lower density, a higher flash point, reduced evaporation loss and a comparable viscosity and water content. The studied RD contained a limited amount of aromatics, with aliphatic hydrocarbons predominantly within the C15 to C18 range. Most individual petroleum hydrocarbons were detected in the PD-dominant diesels, whereas the most abundant hydrocarbons for the RD were alkanes in the <n-C19 carbon range. The typical chemical signature of RD includes clustered peaks within the C15 to C18 range on GC/FID chromatograms coupled with a sharp decline in the abundance of n-alkanes from ∼n-C19 and heavier. These properties are robust indicators of RD, even in RD/PD blends. However, quantifying the RD/PD blending ratios is challenging because of their overlapping chemical compositions. The quantified blending ratios for the blended biodiesel/PD are close to theoretical biodiesel ratios. Our analyses provide valuable insights into the forensic identification of RD, biodiesel, PD and their blends.