Modeling the Vapor Pressure of Biodiesel Fuels

The composition, vapour pressure, and heat capacity of nine biodiesel fuels from different sources were measured. The vapour pressure of the biodiesel fuels is modeled assuming an ideal liquid phase of the fatty acid methyl esters constituting the fuel. New methodologies to calculate the vapour pressure and ideal gas and liquid heat capacities of the biodiesel fuel constituents are proposed. Two alternative optimization scenarios are evaluated: 1) vapour pressure only; 2) vapour pressure constrained with liquid heat capacity. Without physical constraints, significant errors in liquid heat capacity predictions were found whereas the constrained correlation accurately fit both vapour pressure and liquid heat capacity.

Authors:

• O. Castellanos Díaz
• F. Schoeggl
• H. W. Yarranton
• M. A. Satyro
• T. M. Lovestead
• T. J. Bruno

Keywords:

• Biodiesel fuels
• Fatty acid methyl ester
• Heat capacity
• Modeling
• Vapour pressure

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