resumo
To develop reliable models for the densities and viscosities of biodiesel fuel, reliable data for the pure fatty acid esters are required. Densities and viscosities were measured for seven ethyl esters and eight methyl esters, at atmospheric pressure and temperatures from (273.15 to 363.15) K. A critical assessment of the measured data against the data previously available in the literature was carried out. It is shown that the data here reported presents deviations of less than 0.15 % for densities and less than 5 % for viscosities. Correlations for the densities and viscosities with temperature are proposed. The densities and viscosities of the pure ethyl and methyl esters here reported were used to evaluate three predictive models. The GCVOL group contribution method is shown to be able to predict densities for these compounds within 1 %. The methods of Ceriani and Meirelles (CM) and of Marreiro and Gani (MG) were applied to the viscosity data. It is shown that only the first of these methods is able to provide a fair description of the viscosities of fatty acid esters.
palavras-chave
SURFACE-TENSION; PHYSICAL-PROPERTIES; BIODIESEL FUELS; BINARY-MIXTURES; OIL; TEMPERATURES; PREDICTION; ETHANOATE; VOLUMES; BLENDS
categoria
Thermodynamics; Chemistry; Engineering
autores
Pratas, MJ; Freitas, S; Oliveira, MB; Monteiro, SC; Lima, AS; Coutinho, JAP
nossos autores
Maria Jorge Pratas
Gestor de Ciência e Tecnologia
Mariana Belo Oliveira
Bolseiro de pós-Doutoramentoagradecimentos
Received for review January 13, 2010. Accepted July 5, 2010. M.J.P. and M.B.O. acknowledge the financial support from Fundacao para a Ciencia e a Tecnologia through their Ph.D. grants (SFRH/BD/28258/2006, SFRH/BD/29062/2006). S.F. aknowledges a Ph.D. grant from Fundacao Oriente and also financial support from the University of Aveiro.