Estudo exploratorio da aplicabilidade dos meios supercriticos para a extração e o processamento de oleos vegetais com enfase em controle aplicado a unidade extratora

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

Since it was proposed in 20 s, the solvent extraction process for oilseeds has employed petrol-derived solvents. Even thought these extraction agents have been significantly improved in quality, the hexane (nowadays used) still presents detrimental features such as toxicity, non-renewability as well as high flammability. Supercritical solvents, most often the carbon di oxide, on the other hand, have been applied to extract natural products, giving them high qualities and, if operated in a closed cycle, producing no environmental impacts. Intending to investigate the viability of the supercritical extraction process for lipids and to compare it with the conventional liquid hexane extraction process, the state of the art on the mathematical modelling and operational costs was up to dated. To contribute with operational data, not common in the literature, a dynamic model fur a semi-batch supercritical extraction with carbon dioxide was adapted to a numerical solution and simulated on a microcomputer. This numerlcal solution made possible a study of parameter sensitivity and analyses of performances for the cIassical Proportional and advanced DynamicMatrix (DMC) controllers. The analyses ofparameter sensitivity, made by means of a factorial design, had shown that tbe solvent superficial velocity can be used to control oil concentrations in the solid and in the solvent phases, after disturbances in the initial solid oil concentration and solvent inlet concentration.Both kinds of analysed controllers, specially the cIassical Proportional, showed good performances for controlling the residual oil in the solids and the solvent oil content, after disturbances in the initial oil content of the fed solids and in the solvent ínlet concentration. However, in situations in what multiple inputs and outputs are involved, control strategies more complex than the classical Proportional and more suitable than the DMC, as adapted here to the semi-continuous extraction, wiII be necessary to good performances.

ASSUNTO(S)

dioxido de carbono extração (quimica)

ACESSO AO ARTIGO

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