Dissertações em Engenharia Química (Mestrado) - PPGEQ/UNICAMP
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/9657
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Dissertação 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.Dissertação Acesso aberto (Open Access) Transferência de calor com mudança de fase em processos de borbulhamento(Universidade Estadual de Campinas, 1986-04-25) SOUZA, Célio Augusto Gomes de; ANDRADE, Alberto Luiz de; http://lattes.cnpq.br/5905831095854831Heat transfer fenomena with phase change is analyed in a bubbling process, where heated gas hubbies pass through a liquid. The experimental evaporation rate is measured with an equipment which operates with gas feed temperatures in the range of 70 to 285°C, A diffusive transient model is presented in which the simultaneous transfer effects and surface bubble superheating are taken into account to calculate heat and mass transfer coefficients and flow rates. The modeling equations are presented in the explicit form thus permitting the direct calculations of heat and mass transfer rates during the evaporation of a liquid and the testing the predicted values with experimental results. A comparison between the simultaneous and the superheating models showed that at higher gas temperatures and higher residence times , both modeIs reproduce satisfactorily the operational conditions. in order to verify the equipment performance to obtain the bubbling time needed for the attainment of steady state, the liquid equilibrium temperature was theoretically calculated taking into a account the simultaneous and the superheating effects, being these results compared with the experimental values.