Teses e Dissertações defendidas fora da UFPA
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/7305
Teses e Dissertações defendidas fora do âmbito da Universidade Federal do Pará cujos autores(as) sejam servidores(as) técnicos administrativos ou docentes da UFPA
Navegar
Navegando Teses e Dissertações defendidas fora da UFPA por Autor "ARAÚJO, Marilena Emmi"
Agora exibindo 1 - 2 de 2
- Resultados por página
- Opções de Ordenação
Item Acesso aberto (Open Access) Estudo do equilibrio de fases para sistemas óleo vegetal/dióxido de carbono empregando a equação de Peng-Robinson(Universidade Estadual de Campinas, 1997-06-06) ARAÚJO, Marilena Emmi; MEIRELES, Maria Angela de Almeida; http://lattes.cnpq.br/7459851068586682This work is concerned with the prediction of the vapor-liquid equilibria using the Peng-Robinson EOS for systems: fat and oils related compounds/supercritical CO2. The van der Waals mixing rules were employed with two binary interaction parameters. The combining rules proposed by Kwak & Mansoori and Park, Kwak & Mansoori that involve three binary interaction parameters were also used. It has also been studied the extraction of Amazon seed oils with carbon dioxide (pressures of 150-300 bar; temperatures of 50°C-60°C). The effects of the operational conditions on the fatty acids and triglycerides composition of the oils were investigated. A software was developed using Delphi 1.0 for Windows to obtain the binary interaction parameters and for the vapor-liquid equilibria P-T flash calculation. The published pure components' data (Tb, Tc, Pc and vapor pressure) of fatty acids and fatty acid esters were employed to evaluate the methods available for predictions of Tb, Tc and Pc. The Constantinou & Gani and the Somayajulu methods, using experimental values of Tb, were selected for the prediction of Tc and Pc, respectively. The Constantinou & Gani method was selected for the prediction of Tb, Tc and Pc, and the Tu method was selected for the prediction of the acentric factor of fatty acids. The Joback & Reid method was selected for the prediction of Tb and Tc, and the Constantinou & Gani for the prediction of Pc of fatty acid esters. The Vetere correlation was selected for the calculation of the acentric factor for low molecular weight fatty acid esters, and the Tu method for the fatty acid methyl esters' family. The results show that the Peng-Robinson EOS with the van der Waals mixing rules with three combining rules were able to describe qualitatively the vapor-liquid equilibria of the systems studied. There were no significant differences among the three combining rules. The composition in fatty acids and triglycerides of the oils of Cupuacu, Bacuri, Palm Kernel and Passion fruit, extracted with CO2 showed a slight variation for the pressure and temperature ranges studied.Item Acesso aberto (Open Access) Estudo experimental do excesso da energia livre de Gibbs dos sistemas ciclohexano e N-hexano/2-butanol entre 323,15 e 348,15 K(Universidade Estadual de Campinas, 1990-08-21) ARAÚJO, Marilena Emmi; FRANCESCONI, Artur Zaghini; http://lattes.cnpq.br/6523018230610997The main propose or this work was the experimental determination or the excess Gibbs free energy or binary systems of the hydrocarbon/alcohol type. The criteria used for selection of the systems included the expansion or experimental information about, the excess Gibbs free energy and a systematic study of its behaviour with regard to temperature variation and modification in the hydrocarbon chain. The excess Gibbs free energy was determined through isotermal measures or vapor/liquid phase equilíbria. A ¿FISCHER¿ recirculating still,which is a commercial version of the Stage-Muller recirculating still (1961), was used for collecting experimental data. In order to test, the performance of the equipament the vapor pressure curves for ethanol and water in the range 13 to 107 kPa and the vapor/liquid equilibrium Data for the cyclohexane/toluene system at 323,15 K,were determined. The collected data were compared w1t,h literature results. The sstems,cyclohexane/2-butanol and n-hexane/2-butanol were studied at 323,15, 338,15 and 348,15 K. All experimental data were tested with regard to thermodynamic consistency. The excess Gibbs free energy experimental data were correlated through the UNIQUAC associated solution theory, and the UNIQUAC equation. In order to decrease the number of adjustable parameters, two modifications were proposed to the UNIQUAC associated solution theory.