CONICET | Buscador de Institutos y Recursos Humanos

Thepossibility of directly feeding the extract of a liquid-liquid extraction unitto a chemical reactor is analyzed. Anexample of extraction and non-catalytic esterification of naphthenic acids fromacid petroleum crudes is used. Methanolis used both as a solvent and reactant. Separated tests of extraction and reaction are made and the performanceof an integrated process is deduced by computer simulation. Thermodynamic and kinetic parameters forextraction of naphthenic acids from an acid crude were determined. A partition coefficient of m=0.66 at 60 °Cbetween the alcoholic and petroleum phases was found. Three succesive batch extractions with a 1:1vol:vol ratio reduced the acidity from 4.3 to about 1.1 mgKOH/g. Naphthenic acid concentrates were reactedwith supercritical methanol in a batch reactor at high temperatures (280 °C)yielding naphthenic esters. 1-2 h ofreaction with methanol-to-oil molar ratios of 3-6 yielded 92-96% conversionbecause of a relatively low value of the equilibrium constant. Total conversion could however be got withthe highly diluted extracts. Simulationswere run using 3 countercurrent mixer-settlers and a non-catalyticreactor. The results indicated thatextraction/supercritical esterification is a convenient pretreatment step ofacidic feedstocks because of its simplicity, the good quality of thedeacidified feedstock (acidity < 0.5 mgKOH/g), the total removalof the acids and the good properties of the ester product as a fueladditive. Characterization of the methylnaphthenate product showed it had a lower viscosity than the crude or thenaphthenic acids, a high flash point and total miscibility in gasoline,kerosene and Diesel. These and otherproperties showed it could be sent to the Diesel or heating oil pools.

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