Modeling the Vapor Pressure of Biodiesel Fuels

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

Abstract:

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.

Keywords: Biodiesel fuels, Fatty acid methyl ester, Heat capacity, Modeling, Vapour pressure

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1056675

References:

[1] Allen, C. A. W.; Watts, K. C.; Ackman, R. G.; and Peg, M. J. Predicting the Viscosity of Biodiesel Fuels from Their Fatty Acid Ester Composition, Fuel, 78, 1999, 1319-1326.
[2] Goodrum, J. W. Volatility and Boiling Points of Biodiesel from vegetable Oils and Tallow, Biomass and Bioenergy, 22, 2002, 205-211
[3] Ott, L.; and Bruno, T. Variability of Biodiesel Fuel and Comparison to Petroleum-Derived Diesel Fuel: Application of a Composition and Enthalpy Explicit Distillation Curve Method, Energy & Fuel, 22, 2008,2861-2868
[4] Conceiçao, M. M., Roberlúcia, A. C., Silva, F. C., Bezerra, A. F., Fernandes Jr., V. J., and Souza, A. G. Thermoanalytical Characterization of Castor Oil Biodiesel, Renewable & Sustainable Energy Reviews, 11, 2007, 964-975
[5] Yuan, W., Hansen, A. C.; Zhang, Q. Vapor Pressure and Normal Boiling Point Predictions for Pure Methyl Esters and Biodiesel Fuels, Fuel, 84, 2005,943-950
[6] National Institute of Standards and Technology, NIST, NIST/EPA/NIH Mass Spectral Library Version 1.0, USA, 1995
[7] American Oil Chemist-s Society (AOCS), The Lipid Library, USA, 2001
[8] Bruno, T. J., and Svoronos, P. D. N., CRC Handbook of Fundamental Spectroscopic Correlation Charts, Taylor and Francis Group, 2006
[9] Bruno, T. J., and Svoronos, P. D. N., CRC Handbook of Basic Tables for Chemical Analysis, Third Edition, CRC Press, Boca Raton, 2011
[10] Haines, P. J., Thermal Methods of Analysis: Principles, Applications and Problems, Springer, 2002
[11] Weir, R. D., and de Loos, Th. W. Measurement of the Thermodynamic Properties of Multiple Phases, IUPAC, Physical Chemistry Division, Commission on Thermodynamics, Elsevier, The Netherlands, 2005
[12] Knothe, G.; van Gerpen, J., and Krahl, J., The Biodiesel Handbook, AOCS Press, 2005
[13] R├║ži─ìka, K; and Majer, V. Simple and Controlled Extrapolation of Vapor Pressures toward the Triple Point, AIChE J., 42 (6), 1723-1740, 1996
[14] National Institute of Standards and Technology, NIST. ThermoData Engine (TDE) Version 6.0, Pure compounds, Equations of state, Binary mixtures, and Chemical Reactions. NIST Standard reference Database #103b. Thermophysical Research Center. USA. 2011
[15] Roth, A. Vacuum Technology, 3rd edition, North-Holland, Netherlands, 1990
[16] Fulem, M., Private Communication, University of Calgary, Calgary, 2011
[17] Poling, B. E., Prausnitz, J. M., and O-Connell, J. P., The Properties of Gases and Liquids, 5th edition, McGraw-Hill, 2001
[18] Dadgostar, N.; and Shaw, J. A Predictive Correlation for the Constant- Pressure Specific Heat Capacity of Pure and Ill-Defined Liquid Hydrocarbons, Fluid Phase Equilibria, Paper in Press, 2011