resumo
The knowledge and the capability to describe the phase equilibria of binary systems formed by a fatty acid ester and an alcohol are of great interest in biodiesel production, where these mixtures can be found after the transesterification unit and where they must be separated to purify the biodiesel stream and to recover the unreacted alcohol. Despite this interest, little information is available on the vapor liquid equilibria (VLE) of fatty acid ester + alcohol systems. To overcome this lack of data, new VLE measurements of six ester + methanol/ethanol systems were carried at atmospheric pressure. This new experimental data was successfully modeled with the Cubic-Plus-Association equation of state (CPA EoS), with global average deviations of 0.5% for the bubble-point temperatures. In all cases small and temperature independent parameters were enough to adequately describe the measured data. Furthermore a constant value for the cross-association energy parameter was proposed for each alcohol system, as well as a linear correlation for the binary interaction parameter with the ester chain length, making the CPA EoS a powerful predictive model for these systems.
palavras-chave
VAPOR-LIQUID-EQUILIBRIA; BIODIESEL PRODUCTION; 101.32 KPA; CPA EOS; MUTUAL SOLUBILITIES; REFRACTIVE-INDEX; BINARY-MIXTURES; METHANOL; WATER; ACETATE
categoria
Engineering
autores
Oliveira, MB; Miguel, SI; Queimada, AJ; Coutinho, JAP
nossos autores
Mariana Belo Oliveira
Bolseiro de pós-Doutoramentoagradecimentos
Financial support was provided to LSRE by FEDER/POCI/2010. Mariana B. Oliveira acknowledges Fundacao para a Ciencia e a Tecnologia through her Ph.D. (SFRH/BD/29062/2006) scholarship. A. J. Queimacla acknowledges support from POCI/N010/2006.