Microstructure characterization of asphaltenes from atmospheric residue before and after hydroprocessing

A comparative study on microstructure of asphaltenes obtained from an atmospheric residue (AR), a hydroprocessed oil of AR and a blending of AR with high aromatic light cycle oil (LCO) was carried out by element analysis, scanning and transmission electron microscopy (SEM and TEM). Different asphaltene morphologies, smooth surface and porous surface with spherical particles, were observed by SEM before and after hydroprocessing. The results of TEM micrographs show that the aromatic ring stacking of original asphaltene is characterized of long range disorder and short range order, and multi-stacking graphite-like carbon with long range order is observed for hydroprocessed asphaltene. The addition of high aromatic LCO into AR enhances the hydrogenation reactions of asphaltene and inhibits the aggregation of aromatic ring systems under AR hydrotreating.