resumo
The knowledge of fatty acid esters/biodiesels thermodynamic properties is crucial not only for developing optimal biodiesel production and purification processes, but also for enhancing biodiesels performance in engines. This work is intended to apply a simple but reliable theoretically based sound model, the soft-SAFT EoS, as a tool for the development, design, scale-up, and optimization of biodiesels production and purification processes. A molecular model within the soft-SAFT EoS framework is proposed for the fatty acid esters, and the Density Gradient Theory approach is coupled into soft-SAFT for the description of interfacial properties, while the Free-Volume Theory is used for the calculation of viscosities, in an integrated model. For pressures up to 150 MPa, and in the temperature range 288.15-423.15K, density, surface tension, viscosity and speed of sound data for fatty acid methyl and ethyl esters, ranging from C-8:0 to C-24:0, with up to three unsaturated bonds, are described with deviations inferior to 5%. Finally, in order to validate the predictive ability of the model to be applied in the biodiesel groundwork, the high pressure densities and viscosities for 8 biodiesels were predicted with the soft-SAFT EoS, reinforcing the validity of the approach to obtain reliable predictions for engineering purposes. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
palavras-chave
DIRECTIONAL ATTRACTIVE FORCES; LENNARD-JONES CHAINS; FATTY-ACID METHYL; DENSITY EXPERIMENTAL MEASUREMENTS; ASSOCIATING FLUID THEORY; VAPOR-LIQUID-EQUILIBRIA; HEAVY N-ALKANES; PHASE-EQUILIBRIA; IONIC LIQUIDS; ETHYL-ESTERS
categoria
Engineering
autores
Oliveira, MB; Freitas, SVD; Llovell, F; Vega, LF; Coutinho, JAP
nossos autores
Mariana Belo Oliveira
Bolseiro de pós-Doutoramento
agradecimentos
S.V.D. Freitas acknowledges a Ph.D. Grant from Fundacao para a Ciencia e a Tecnologia through his Ph.D. grant (SFRH/BD/51476/2011), Fundacao Oriente and also financial support from the University of Aveiro. M. B. Oliveira acknowledges for her Post-Doctoral grant (SFRH/BPD/71200/2010) and F. Llovell for a TALENT contract from the Catalan Government and MATGAS. CICECO is being founded by FCT through project PEst-C/CTM/LA0011/2013. Financial support was also given by the Spanish Government under project CENIT SOST-CO2. Additional support from Carburos Metalicos, Air Products Group, and the Catalan Government was also provided (2009SGR-666).