SUPERCRITICAL PROPANE SEPARATION OF DEASPHALTED OIL AND CARBON-PRECURSOR PITCH FROM HEAVY PETROLEUM RESIDUUM

The feasibility of the use of a petroleum vacuum-distillation residuum as a feedstock for carbon applications was investigated using a semic ontinuous supercritical propane (C3H8) extraction system. Experiments were carried out under different conditions to ascertain the effects o f system pressure and temperature on the yields of extracted oils and the properties of residual pitches. The extraction residue obtained ne ar the critical temperature and over the critical pressure of propane solvent showed appropriate properties as a precursor pitch for carbon materials, representing superior yields, high asphaltene contents, low toluene insolubles and the adequate softening point of 401-424 K. The extraction yields of deasphalted oil were increased as the system pre ssure was increased corresponding to the increased density of propane solvent. No difference in the yields and properties of residual pitche s were observed at the experiments performed in the vicinity of the cr itical temperature of propane.