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

Long term stability of visbroken residues (150-degrees-C+) were studie d in terms of sediment yield and viscosity. Residues were obtained thr ough Soaker visbreaking of petroleum short residue on a pilot plant un der different operating severities. The effect of storage time and com positional data of residue (150-degrees-C+) as well as structural para meters of asphaltenes on sediment yield are reported. Qualitative char acterization of sediment was done employing infrared spectroscopy Whil e an increasing trend in sediment yield is obtained with asphaltene an d olefin content of residue (150-degrees-C+), a decreasing trend with H(al)/H(ar) of asphaltenes is shown. Further the sediment yield is fou nd to increase with pyrrolic compounds in the residue (150-degrees-C+) . The comparison of IR spectra of sediments as such and their THF-inso luble portion reveals that latter still contain aliphatic groups predo minantly naphthenes condensed with aromatic clusters.