Estudo do equilíbrio líquido-vapor do sistema água+etanol+líquido iônico visando a separação do álcool anidro
Anhydrous ethanol is used in chemical, pharmaceutical and fuel industries. However, current processes for obtaining it involve high cost, high energy demand and use of toxic and pollutant solvents. This problem occurs due to the formation of an azeotropic mixture of ethanol + water, which does not a...
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| Materyal Türü: | Dissertação |
| Dil: | por |
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Universidade Federal do Rio Grande do Norte
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| Online Erişim: | https://repositorio.ufrn.br/jspui/handle/123456789/15834 |
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| Özet: | Anhydrous ethanol is used in chemical, pharmaceutical and fuel industries.
However, current processes for obtaining it involve high cost, high energy demand and use of
toxic and pollutant solvents. This problem occurs due to the formation of an azeotropic
mixture of ethanol + water, which does not allow the complete separation by conventional
methods such as simple distillation. As an alternative to currently used processes, this study
proposes the use of ionic liquids as solvents in extractive distillation. These are organic salts
which are liquids at low temperatures (under 373,15 K). They exhibit characteristics such as
low volatility (almost zero/ low vapor ), thermal stability and low corrosiveness, which make
them interesting for applications such as catalysts and as entrainers. In this work,
experimental data for the vapor pressure of pure ethanol and water in the pressure range of 20
to 101 kPa were obtained as well as for vapor-liquid equilibrium (VLE) of the system ethanol
+ water at atmospheric pressure; and equilibrium data of ethanol + water + 2-HDEAA (2-
hydroxydiethanolamine acetate) at strategic points in the diagram. The device used for these
experiments was the Fischer ebulliometer, together with density measurements to determine
phase compositions. The experimental data were consistent with literature data and presented
thermodynamic consistency, thus the methodology was properly validated. The results were
favorable, with the increase of ethanol concentration in the vapor phase, but the increase was
not shown to be pronounced. The predictive model COSMO-SAC (COnductor-like Screening
MOdels Segment Activity Coefficient) proposed by Lin & Sandler (2002) was studied for
calculations to predict vapor-liquid equilibrium of systems ethanol + water + ionic liquids at
atmospheric pressure. This is an alternative for predicting phase equilibrium, especially for
substances of recent interest, such as ionic liquids. This is so because no experimental data
nor any parameters of functional groups (as in the UNIFAC method) are needed |
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