Variability of Biodiesel Fuel and Comparison to Petroleum-Derived Diesel Fuel: Application of a Composition and Enthalpy Explicit Distillation Curve Method
Thomas J. Bruno, Lisa S. Ott
We have recently introduced several important improvements in the measurement of distillation curves for complex fluids. This new method is a significant improvement over current approaches, featuring (1) a composition-explicit data channel for each distillate fraction (for both qualitative and quantitative analysis), (2) temperature measurements that are true thermodynamic state points that can be modeled with an equation of state, (3) temperature, volume, and pressure measurements of low uncertainty suitable for equation of state development, (4) consistency with a century of historical data, (5) an assessment of the energy content of each distillate fraction, (6) trace chemical analysis of each distillate fraction, (7) corrosivity assessment of each distillate fraction. Herein, we compare the distillation curves of four different biodiesel fuel samples to assess possible variations in the distillation curves based on the source of the fuel. Next, we utilize the composition-explicit data channel to characterize distillate cuts of each of the four biodiesel fuels in terms of available energy content. The measure we use for the fluid energy content of each distillate fraction is the composite enthalpy of combustion. On a molar basis, the enthalpy of combustion of the four biodiesel fuels slightly increased with increasing distillation temperature. The biodiesel fuel sample with the highest methyl oleate content had a somewhat different distillation curve and distillate fraction enthalpies of combustion that were higher than the other three biodiesel fuels. Then, we compare both the distillation curves and enthalpies of combustion as a function of distillate fraction of the four biodiesel fuels with one petroleum-derived diesel fuel. Importantly, on a molar basis the enthalpies of combustion of biodiesel fuels were greater in every distillate fraction compared to petroleum-derived diesel fuel; however, on a mass or volume basis, the petroleum-derived diesel fuel sample was more energetic.
biodiesel fuel, distillation curve, enthalpy of combustion, petroleum-derived diesel fuel.
and Ott, L.
Variability of Biodiesel Fuel and Comparison to Petroleum-Derived Diesel Fuel: Application of a Composition and Enthalpy Explicit Distillation Curve Method, Energy and Fuels, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=50637
(Accessed May 31, 2023)