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ispartof: SEPARATION AND PURIFICATION TECHNOLOGY vol:313 status: accepted

Optimization of the extraction process for reducing aromatic and/or polyaromatic compounds is of primary interest in crude oil refining. Several solvents are described for carrying out such operations (furfural, N-methyl-pyrrolidone -NMP-, dimethyl-sulfoxide -DMSO-, …) and experimental data and model description are required for the correct design of the separation operations and the optimization of the conditions. In this work, liquid-liquid equilibria (LLE) data were determined for oil multicomponent mixtures formed by n-dodecane + mono-aromatic + poly-aromatic with NMP at ambient temperature (298.15 K) and pressure and covering a wide range of the solvent/oil ratios. A new analytical method based on NMR was developed, calibrated, and tested to fully determine the composition of equilibrium phases despite the high number of compounds. Obtained values for distribution constants and selectivities are higher than one and ranging 1-15, respectively, for aromatic compounds and even higher for polyaromatic components. Thus NMP appears as a suitable solvent for carrying both separations. The experimental data were predicted by several versions of the UNIFAC model, including the UNIFAC, modified UNIFAC (Dortmund), modified UNIFAC (NIST), and UNIFAC, including fitting parameters. Overall, modified UNIFAC (Dortmund) yields the best results, even when deviations obtained for some of the compositions are around 40% of the value, and simulations carried out with such models should be considered cautiously

Monoacylglycerols (MAGs) can be produced by lipase-catalyzed glycerolysis of oils and fats at atmospheric pressure and low temperature. The use of organic solvents as reaction media helps to create a homogeneous reaction system between the immiscible reactants glycerol and oil. In this work liquid–liquid equilibrium at two different temperatures (303.2 and 323.2 K) and at atmospheric pressure has been determined for two solvent-systems in the glycerolysis of fish oil (sardine oil): glycerol + sardine oil + tert-butanol and glycerol + sardine oil + tert-pentanol. From the experimental solubility (binodal) curves and tie-lines, it could be observed that the system mutual solubility does not significantly increase by increasing temperature from 303.2 to 323.2 K. The Othmer–Tobias correlation was used to analyze the consistency of the tie-line data. The experimental liquid–liquid data were correlated satisfactorily by using the NRTL model for the activity coefficient calculation., MINECO (CTQ2012-39131-C02-01) and CDTI (Ref. IDI-20111225)

International audience; The present work focuses on the thermodynamic modeling of the Bunsen section of the Iodine-Sulfur thermochemical cycle for hydrogen production on the basis of a combination of UNIQUAC activity coefficient and solvation models. The complexity of the material system, two immiscible electrolyte aqueous phases (H$_2$SO$_4$ rich and HI$_x$ rich), is managed by defining an equivalent material system able to capture the main physical phenomena. Only the key species involved and their mutual interactions are taken into account, reducing the number of parameters to be estimated from a hundred to only 15. Results show a good agreement with published experimental data, with a better description of the impurities in the HIx phase than in the sulfuric acid phase.

The process of recovery by liquid–liquid extraction of ethanol manufactured in a fermentation process could be improved by using solvents as 1-dodecanol that have a good separation factor. In this work, liquid–liquid equilibrium data for the ternary system water–ethanol–1-dodecanol have been determined experimentally at 5, 8, 15, 23 and 30 ºC. The results show different shapes of the equilibrium diagrams depending on the temperature. A region with three phases (liquid–liquid–solid) appears in the temperature range between 8 and 23 ºC. The lowest temperature at which a water–ethanol–dodecanol mixture cannot be split in two liquid phases has been determined as 8 ºC. The authors wish to thank the DGICYT (Spain) for the financial aid with Project PPQ2003-03385.

Liquid–liquid equilibrium data for the ternary system 1-butanol–1-propanol–water have been determined experimentally at 25, 50, 85 and 95ºC. The results obtained have been correlated simultaneously by the UNIQUAC method obtaining two sets of interaction parameters: one of them independent of the temperature and the other with a linear dependence. Both sets of parameters fit the experimental results well which is an improvement on using parameters depending of the temperature of 15%. The authors wish to thank the Generalitat Valenciana Spain for the financial help of the Project GV-3174r95 and to DGES for the financial aids of project PB96-0338.