CONICET | Buscador de Institutos y Recursos Humanos

The possibility of directly feeding the extract of a liquid-liquid extraction unit to a chemical reactor is analyzed. An example of extraction and non-catalytic esterification of naphthenic acids from acid petroleum crudes is used. Methanol is used both as a solvent and reactant. Separated tests of extraction and reaction are made and the performance of an integrated process is deduced by computer simulation. Thermodynamic and kinetic parameters for extraction of naphthenic acids from an acid crude were determined. A partition coefficient of m=0.66 at 60 °C between the alcoholic and petroleum phases was found. Three succesive batch extractions with a 1:1 vol:vol ratio reduced the acidity from 4.3 to about 1.1 mgKOH g-1. Naphthenic acid concentrates were reacted with supercritical methanol in a batch reactor at high temperatures (280 °C) yielding naphthenic esters. 1-2 h of reaction with methanol-to-oil molar ratios of 3-6 yielded 92-96% conversion because of a relatively low value of the equilibrium constant. Total conversion could however be got with the highly diluted extracts. Simulations were run using 3 countercurrent mixer-settlers and a non-catalytic reactor. The results indicated that extraction/supercritical esterification is a convenient pretreatment step of acidic feedstocks because of its simplicity, the good quality of the deacidified feedstock (acidity < 0.5 mgKOH g-1), the total removal of the acids and the good properties of the ester product as a fuel additive. Characterization of the methyl naphthenate product showed it had a lower viscosity than the crude or the naphthenic acids, a high flash point and total miscibility in gasoline, kerosene and diesel. These and other properties showed it could be sent to the diesel or fuel oil pools.