Thermoanalytical evaluation of asphaltene heavy fractions obtained from petroleum extraction

Abstract Precipitation and deposition of asphaltenes, heavy fraction of crude oil, could be considered one of the major problems affecting the chain of production, transportation, and flow assurance. This heavy fraction aggregates even at low concentrations, causing problems throughout the marketing chain. Additionally, they can form coke when thermally decomposed, which is also responsible for catalyst deactivation during the processing phase. This work aims to accomplish the separation and thermoanalytical characterization of heavy fractions, whose major components are asphaltenes, present in petroleum samples from Brazilian basins. The extraction process used was in accordance with ASTM 6560. Three crude oil samples with different °API were studied as their high molecular weight extracted fractions. Thermogravimetric results indicated that the heavy fraction, retained after the reflux stage, exhibited a thermal behavior profile more similar to the asphaltene standard than the material obtained in the final experiment. Fourier transform infrared spectra showed similar absorption bands in the asphaltene standard as the extracted fraction named A sample, with almost the same intensity.