Evaluation of Organic Solvent Efficiency in Asphaltene Precipitation from Brazilian Petroleum and Analysis of Asphaltene and Maltenic Fractions by Different Instrumental Techniques

Asphaltenes are a complex fraction of the crude oil without paraffin, soluble in aromatic solvents and insoluble in n-alkanes of low molecular weight, being found in the oil stabilized by resins. This class of compounds deserves attention in the oil industry because the problems it causes, such as their precipitation in the well and flow lines. This work evaluated four solvents in the asphaltene precipitation of two Brazilian oils, and the chemical composition of asphaltene and maltene fractions obtained. Results showed a significant influence of the solvent in the deposited amount of asphaltene, and n-pentane was more efficient than other solvents. Also, it was found by IR spectroscopy and elemental analysis of CHN that changing the solvent does not change the elemental composition and the types of functional groups of precipitated asphaltenes. Furthermore, it was observed by NMR of H-1 that the asphaltenes obtained have different composition for the two used oils.