Nrtl
Mostrando 25-36 de 68 artigos, teses e dissertações.
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25. Experimental determination of vapor-liquid equilibrium data of binary mixtures of fatty acids through Differential Scanning Calorimetry / Determinação experimental de dados de equilibrio liquido-vapor de misturas binarias de componentes de oleos vegetais atraves da calorimetria diferencial exploratoria
This work will contribute to some unpublished data of phase equilibria of compounds that form the biodiesel, which arouses the interest immediately. Vapor-liquid equilibrium (VLE) data for three binary mixtures of saturated fatty acids have been successfully measured through differential scanning calorimetry (DSC). These data are of great interest to the ind
Publicado em: 2009
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26. Estudo termodinamico do equilibrio liquido-liquido visando a remoção do enxofre do oleo diesel com liquidos ionicos / Thermodynamic study of liquid-liquid equilibrium aiming sulfur removal by using ionic liquids
The sulfur contaminants more difficult to remove from diesel oil by hydrodesulfuration process (HDS) are the sterically hindered aromatic compounds, like dibenzothiophene (DBT), and its alkylated derivatives 4-methyl-dibenzothiophene (4-MDBT) and 4,6-dimethyl-dibenzothiophene (4,6-DMDBT), commonly called DBTs. Increasing the number of methyl groups attached
Publicado em: 2009
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27. Dynamic optimization of the benzene extractive distillation unit
A mathematical model has been developed for describing the dynamic operation of the N-formylmorpholine extractive distillation column and the corresponding solvent recovery column in the benzene extraction plant. The NRTL equation was used to calculate the equilibrium and thermodynamic properties of the mixtures. The validity of the model in terms of tempera
Brazilian Journal of Chemical Engineering. Publicado em: 2008-12
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28. Phase stability analysis of liquid-liquid equilibrium with stochastic methods
Minimization of Gibbs free energy using activity coefficient models and nonlinear equation solution techniques is commonly applied to phase stability problems. However, when conventional techniques, such as the Newton-Raphson method, are employed, serious convergence problems may arise. Due to the existence of multiple solutions, several problems can be foun
Brazilian Journal of Chemical Engineering. Publicado em: 2008-09
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29. Separation of ethanol and water by extractive distillation with salt and solvent as entrainer: process simulation
The aim of this work is to simulate and analyze an extractive distillation process for azeotropic ethanol dehydration with ethylene glycol and calcium chloride mixture as entrainer. The work was developed with Aspen Plus® simulator version 11.1. Calculation of the activity coefficients employed to describe vapor liquid equilibrium of ethanol - water - ethyl
Brazilian Journal of Chemical Engineering. Publicado em: 2008-03
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30. Equilibrio liquido-liquido em sistemas aquosos bifasicos agua + PEG 8000 + sal : determinação experimental e modelagem termodinamica / Liquid-liquid equilibrium in aqueous bifasic systems water + PEG 8000 + salt : experimental determination and thermodynamic modelling
In this work, experimental data of the liquid-liquid equilibrium for the aqueous twophase systems water + PEG8000 + magnesium sulfate and water + PEG8000 + sodium sulfate were determined at 25 e 50°C. The compositions of both equilibrium phases were obtained by a gravimetric method, using the lyofilization (freeze-drying) technique for the water determinati
Publicado em: 2008
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31. Simulation and cost analyses in the biodisel production using vegetable oils / Simulação e analise de custos na produção de biodisel a partir de oleos vegetais
Previous works on kinetic data of transesterification reactions of soy, palm, castor, and jatropha curcas oils were used as starting point for the simulation studies carried out in this thesis. It was found that the velocity of the castor bean oil transesterification reaction was higher than for the other oils analyzed, and an explanation for this fact was s
Publicado em: 2008
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32. Liquid-liquid equilibrium for the system of rice brain oil + commercial oleic acid + anhydrous ethanol + hexane / Determinação de dados de equilibrio liquido-liquido de sistemas oleo de farelo de arroz, acido graxo, etanol, hexano
A extração de óleos vegetais com solvente possui a vantagem de operar a temperaturas menores em relação às usadas na extração mecânica, permitindo também a extração de outros compostos desejáveis da semente oleaginosa. Hexana é, geralmente, utilizada para extrair óleo por lixiviação, porém é inflamável e suspeita de causar danos à saúde
Publicado em: 2008
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33. Correlation of (liquid + liquid) equilibrium of systems including ionic liquids
Ionic liquids are neoteric, environmentally friendly solvents (since they do not produce emissions) composed of large organic cations and relatively small inorganic anions. They have favorable physical properties, such as negligible volatility and wide range of liquid existence. Moreover, many different cations and anions can be used to synthesize ionic liqu
Brazilian Journal of Chemical Engineering. Publicado em: 2007-03
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34. Evaluation of the liquid-liquid extraction process with salt addition for organic acid recovery and purification / Avaliação do processo de extração liquido-liquido com a adição de sais para recuperação e purificação de acidos organicos
This study aims a critical evaluation of the liquid-liquid extraction process of organic acids, produced by fermentation. The organic acids of interest in this work are: citric acid, malic acid, succinic acid and tartaric acid. The study includes the recovery and the purification of the chosen organic acids, the thermodynamic characterization of the systems,
Publicado em: 2007
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35. Contribuição ao estudo termodinâmico das soluções de ácido acetilsalicílico.
O ácido acetilsalicílico é um dos medicamentos mais vendidos no mundo e pouco foi realizado no sentido de caracterizar seu comportamento em solução. O presente trabalho visou contribuir no sentido de determinar as curvas de solubilidade e os parâmetros de equilíbrio termodinâmico dos modelos de Margules, Van Laar, Wilson, NRTL, UNIFAC, Teoria das Sol
Publicado em: 2007
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36. Experimental determination and thermodynamic modeling of equilibrium phase data of binaries and ternary mixtures containing acetone, water and cumene / Determinação experimental e modelagem termodinamica de dados de equilíbrio de fases de misturas binarias e ternaria contendo acetona, agua e cumeno
On projecting separation processes it is essential the knowledge of the behavior of the phases in equilibrium. The present work involved the study of the phase equilibrium of mixtures containing acetone, water and cumene, which are very important in the phenol industry. The components water and cumene are partially miscible, and in the distillation of the mi
Publicado em: 2007