ABSTRACT
The fraction compositions, group compositions and structure compositions of seven catalytic stocks were determined by means of vacuum distillation, mass spectrum, element analysis and molecular mass measurement. The effects of the compositions of different catalytic stocks on catalytic cracking reactions were discussed. It is shown that tae gum and asphaltene in the seven catalytic stocks were not very high except residual oil; The saturated hydrocarbon in the seven were all higher; Aromatic contents were lower except slurry oil and recycle oil, therefore, the seven catalytic stocks except slurry oil and recycle oil are all good feedings to catalytic cracking unit. The results also show Liaohe oil turns heavier from low sulphur middle-paraffin base to low sulphur naphthene-middle base.