Separation of Model Petroleum Heavy Fraction by Equilibrium Extraction

For the separation of petroleum-derived heavy fractions by solvent extraction, the liquid-liquid equilibrium extraction of model heavy fractions, binary and multicomponent model oils, with aqueous methanol solutions was measured, and the effects of nitrogen heterocyclic and other coexisting compounds on the equilibrium extraction were studied. The distribution coefficient increased in the following order of the group compounds; alkanes, aromatics and heterocyclic compounds when the carbon numbers in the molecules of interest were same, and it decreased with an increase in the carbon number of the compound among the respective groups. The coefficients for indoles and quinolines were comparable, and those of carbazoles were smaller. The liquid-liquid equilibrium of nitrogen heterocyclic compounds with the multicomponent system was similar with that with the binary system, and the approximate trend of liquid-liquid equilibrium in the multicomponent system could be evaluated based on the results of simpler systems.