EFFECT OF COMPOSITION ON LONG-TERM STABILITY OF VISBROKEN FUEL OILS

Long term stability of visbroken residues (150-degrees-C+) were studied in terms of sediment yield and viscosity. Residues were obtained through Soaker visbreaking of petroleum short residue on a pilot plant under different operating severities. The effect of storage time and compositional data of residue (150-degrees-C+) as well as structural parameters of asphaltenes on sediment yield are reported. Qualitative characterization of sediment was done employing infrared spectroscopy While an increasing trend in sediment yield is obtained with asphaltene and olefin content of residue (150-degrees-C+), a decreasing trend with H(al)/H(ar) of asphaltenes is shown. Further the sediment yield is found to increase with pyrrolic compounds in the residue (150-degrees-C+). The comparison of IR spectra of sediments as such and their THF-insoluble portion reveals that latter still contain aliphatic groups predominantly naphthenes condensed with aromatic clusters.