Pressure Controlled Advanced Distillation Curve Analysis on Alternative Fuels
Bret Windom, Tara M. Lovestead, Thomas J. Bruno
Biodiesel fuel is an alternative fuel that can be derived from a number of renewable feedstocks including plant and vegetable oils, algae, animal fats, waste oils, etc. The fatty acid methyl ester (FAME) profile, and thus the resultant properties, of the biodiesel fuel depend significantly on the feedstock. Thus, a great amount of research is involved with characterizing physical properties, combustion properties, and engine performance of biodiesel fuels derived from a number of feedstocks. An important and informative property that is measured for complex fluid mixtures is the distillation curve. A well established and improved method over the current ASTM standard test methods for distillation curve measurement, is the advanced distillation curve (ADC) method. The ADC approach provides temperature, volume and pressure measurements of low uncertainty, while incorporating a composition explicit data channel for each distillate fraction allowing for the ability to quantitatively track the fluids composition and compositional related properties versus volatility. Recently, a new feature has been added to the ADC protocol allowing for precise reduced pressure distillation curve measurement, which is especially applicable to fluids that undergo thermal degradation at atmospheric pressure as a result of their high normal boiling temperatures. Volatility of a commercial soy based biodiesel fuel (SME) and a cuphea derived biodiesel fuel (CME), a newly investigated plant feedstock because of its unique FAME profile and ability to grow in temperate climates, were investigated with the well established atmospheric ADC method. The volatility of the soy and cuphea based biodiesel fuels were also investigated using the newly developed reduced pressure ADC method. Differences in volatility were noticed when measured at reduced pressures, indicating thermally activated sample polymerization.