Comparative Morphological Study of Asphaltenes in Cuban Crude Using N-Pentane and N-Hexane as Precipitating Agent

Abstract

The components of petroleum are grouped into four organic classes such as: Saturated, Aromatic,Resins and Asphaltenes. Asphaltenes are compounds with a complex structure and high molecularweight, made up by carbon rings linked to alkyl chains and cycloalkanes in addition to heterocycliccompounds with. Nitrogen, Sulphur, and Oxygen. Their precipitation of compounds is associated withprocess of production, transportation and refining of crude oil. Recent studies have proved that asphalteneprecipitates vary depending on the precipitating agent used. The research objective in this study isdeveloping a comparative morphological evaluation to asphaltene samples in crude oils from Seboruco,Santa Cruz, Cabaña and Pina. The asphalting precipitations were obtained employed ASTMD-6560-00,using n-pentane and n-hexane as precipitation agents. It was characterized through the use of a ScanningElectron Microscope using 20 KV acceleration. Solids made up by overlapping flakes linked toform agglomerates were obtained with n-hexane and solids with a higher porosity were obtained withn-pentane. Such behavior is attributed to the occupied spaces where resins were initially. The quantityof precipitate that was obtained with n-pentane is higher than the one obtained with the use of n-hexane.