resumo
Biodiesels have several known components in their composition. The majority of components is well described in the literature, but a minority of components are poorly characterized. These are however required to develop reliable models to predict the biodiesel behavior. This work considers minor components of biodiesel: the polyunsaturated compounds (in C18), the monounsaturated (in C16, C20, and C22), and the long-chain saturated esters. In this work, densities and viscosities of pure fatty acid ester minor components of biodiesel fuel were measured (three ethyl esters and seven methyl esters), at atmospheric pressure and temperatures from (273.15 to 373.15) K. Correlations for the densities and viscosities with temperature are proposed. Three predictive models were evaluated in the prediction of densities and viscosities of the pure ethyl and methyl esters here reported. The GCVOL group contribution method is shown to be able to predict densities for these compounds within 1.5 %. The methods of Ceriani et al. (CM) and of Marrero et al. (MG) were applied to the viscosity data. The first show a better predictive capacity to provide a fair description of the viscosities of the minority esters here studied.
palavras-chave
SURFACE-TENSION; OIL; FUELS; TEMPERATURE
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
Maria Jorge Pratas acknowledges the financial support from Fundacao para a Ciencia e a Tecnologia through her Ph.D. grant (SFRH/BD/28258/2006). Samuel Freitas acknowledges a Ph.D. grant from Fundacao Oriente and also financial support from University of Aveiro.