Measurement and Prediction of Biodiesel Volatility

Vapor pressure directly affects the quality of ignition, atomization, and combustion of a fuel. Lower values lead to delayed ignition, poor atomization, and problematic combustion. Biodiesel fuels might present these problems because they have lower vapor pressure compared to that of petrodiesel. Similar to other properties, however, the magnitude of this property depends upon the composition of fatty acid alkyl esters in biodiesel; therefore, the knowledge of the relationship between these two variables is of great importance. This work reports the vapor pressures of 3 pure methyl esters and 10 biodiesel fuels. The experimental data were used to evaluate the predictive ability of Yuan's, Ceriani's, and cubic-plus-association equation of state (CPA EoS) models for its description. The results underline the good capacity of Yuan's and CPA models for describing the experimental data for all biodiesel fuels studied here, presenting an overall average temperature difference (O Delta T-m) of 1.12 and 1.25 K, while the overall average deviations (OARDs) in vapor pressure are 3.41 and 0.80%, respectively.