Compositional and structural changes in short residues during visbreaking

Compositional and structural parameters of short residue (feed), visbroken products (500 °C + ) and their asphaltenes were estimated using various separation and instrumental analytical techniques. The variation of these parameters with severity of operation measured in terms of wt% yield of 150 °C − were used to predict the reactions taking place during visbreaking. The reactions are: dealkylation and breaking off of paraffinic chains, breaking of C-S bonds in residue and, aromatization of naphthenic structures. In asphaltenes, dealkylation is the major reaction which facilitates condensation of aromatic clusters