Extraction of aromatic and polyaromatic compounds with NMP: experimental and model description

Optimization of the extraction process for reducing aromatic and/or polyaromatic compounds is primary interest in crude oil refining. Several solvents are described carrying out such operations (furfural, N-methyl-pyrrolidone -NMP-, dimethyl-sulfoxide -DMSO-, …) and experimental data model description required correct design separation optimization conditions. In this work, liquid-liquid equilibria (LLE) were determined multicomponent mixtures formed by n-dodecane + mono-aromatic poly-aromatic with NMP at ambient temperature (298.15 K) pressure covering a wide range solvent/oil ratios. A new analytical method based on NMR was developed, calibrated, tested to fully determine composition equilibrium phases despite high number compounds. Obtained values distribution constants selectivities higher than one ranging 1-15, respectively, even components. Thus appears as suitable solvent both separations. The predicted several versions UNIFAC model, including UNIFAC, modified (Dortmund), (NIST), fitting parameters. Overall, (Dortmund) yields best results, when deviations obtained some compositions around 40% value, simulations carried models should be considered cautiously