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Supercritical CO 2 Extraction of Oilseeds: Review of Kinetic and Equilibrium Models

2006; Taylor & Francis; Volume: 46; Issue: 2 Linguagem: Inglês

10.1080/10408390500526514

1549-7852

José M. del Valle, Juan C. de la Fuente,

Adsorption, diffusion, and thermodynamic properties of materials

Mass transfer models on supercritical carbon dioxide (SC-CO 2 ) extraction of vegetable oils are reviewed, that may facilitate the scale-up of laboratory data for industrial design purposes. Reviewed mechanisms of oil transport within the solid matrix include the desorption from the solid, the formation of a shrinking core of condensed oil in a non-adsorbing porous matrix, and diffusion in a homogenous medium. Analyzed simplificat ions of a general mass transfer model include external control of mass transfer rates, internal control of mass transfer rates, consideration of a linear driving force, and steady state approximations, among others. More complex two-stage models, and critical comparisons of some of the proposed models are also included. Trends for the external mass transfer coefficient and effective diffusivity in the solid matrix from studies on SC-CO 2 extraction of oil from vegetable substrates are thoroughly discussed and contrasted with those obtained using simpler model systems. The possible effect of the axial dispersion on the rate of extraction is also discussed. Finally, the high-pressure vegetable oil-CO 2 phase equilibrium is discussed in connection with its influence on the mass transfer process. Special emphasis is given to the role of the solid matrix on high-pressure phase equilibrium. Keywords: supercritical fluid extractioncarbon dioxideoilseedmass transferphase equilibriummodelingscale-up ACKNOWLEDGEMENTS The present work was funded by Fundación Andes (Argentina-Brazil-Chile Cooperation Project C-13600/5) and Fondecyt (Project 103-0375) of Chile. Fruitful discussions with Dr. Fernando L.P. Pessoa (School of Chemistry, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil) and Dr. Miguel Mattea (Dept. Chemical Technology, Universidad Nacional de Rio Cuarto, Rio Cuarto, Argentine) are thankfully acknowledged. This review was completed during the sabbatical leave of JMdV at the Technische Universität Hamburg-Harburg (Germany). Facilities given to the author by Prof. Brunner and his group in Arbeitsbereich Thermische Verfahrenstechnik are greatly acknowledged.