Browsing by Author "Perez Correa, J. R."

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    Dynamic modelling of copper solvent extraction mixer-settler units
    (PERGAMON-ELSEVIER SCIENCE LTD, 2009) Moreno, C. M.; Perez Correa, J. R.; Otero, A.
    The copper Leaching, Solvent Extraction and Electrowinning circuit (LX-SX-EW) is one of the most effective processes for extracting copper from low grade ores. This work focuses on the liquid-liquid extraction SX sub-process, since many difficult to handle operational problems within LX-SX-EW circuits are related to SX malfunction. Controlling these problems better can reduce operational costs and increase recovery and copper production. Realistic dynamic simulation is a standard tool nowadays to design and assess more effective control strategies. In this work we present a general dynamic model for SX mixer-settlers, and applied it to two different units, one located in an extraction stage and the other in a stripping stage of a copper plant. The model includes a non-trivial settler hydrodynamics represented by a set of nonlinear differential equations for both mixer and settler units. The mixer is modelled as a continuous stirred tank reactor and the settler as a hydrodynamic circuit combining series and parallel connections of continuous stirred tank and plug flow reactors. The model was calibrated with industrial plant data, resulting in realistic simulations of outlet copper concentrations. Using the proposed model, we obtained better fitting than that achieved with simpler settler models that include only a time delay. The model fitting parameters provide sufficient flexibility to accurately reproduce the dynamics of different units in industrial plants. (C) 2009 Elsevier Ltd. All rights reserved.
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    Modelling methanol recovery in wine distillation stills with packing columns
    (ELSEVIER SCI LTD, 2011) Carvallo, J.; Labbe, M.; Perez Correa, J. R.; Zaror, C.; Wisniak, J.
    Methanol is a well known toxic congener that contaminates many spirits. Chilean legislation indicates that methanol content in wine distillates should not exceed 1.5 g/L absolute alcohol (a. a.). To achieve this stringent limit, distillers need new tools to improve their operational policies since trial and error experiments are too slow. In this paper, a fast pseudo-stationary simulator for batch distillations in packed bed columns was developed. Packed bed columns are preferable for batch productions of fruit wine distillations since they have a wider range of stable hydraulic operations. The model was solved using orthogonal collocations and considers a liquid vapour equilibrium model of the ternary water-ethanol-methanol mixture, which accounts for most of the volatiles in wine. Simulations compared favourably with our own laboratory batch distillations of water-ethanol-methanol mixtures. In addition, our model simulations were able to qualitatively reproduce the results reported in the literature for methanol recovery in experimental batch distillations. Ethanol recovery errors were within measurement errors, while methanol simulations showed a 3% bias by the end of the distillation. Hence, the developed model is accurate and could be used to explore optimal operational policies in order to minimize methanol content in the heart cut used in the final product. (C) 2011 Elsevier Ltd. All rights reserved.
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    Spinning cone column isolation of rosemary essential oil
    (ELSEVIER SCI LTD, 2010) Graber, M. F.; Perez Correa, J. R.; Verdugo, G.; Del Valle, J. M.; Agosin, E.
    Chemical compositions of rosemary (Rosmarinus officinalis L.) essential oil isolated using different processes, steam distillation and a spinning cone column (SCC), and harvested at different times, spring and autumn, were compared. The effect SCC operating parameters had on yields was also studied. The method used for isolating the oil influenced its composition and yield. The main components found were: camphor, beta-myrcene and 1,8-cineole. SCC derived oils were more consistent and richer, on average, in oxygenated Compounds than steam distilled oils. Furthermore, citronellol, chrysanthenone, piperitone and thymol were detected in SCC oils but not in their steam distilled counterparts. SCC yields were more consistent at a 1/40 dilution while higher yields were achieved at the same dilution spinning at 570 rpm, (C) 2009 Elsevier Ltd. All rights reserved.