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

ABSTRACT

The feasibility of the use of a petroleum vacuum-distillation residuum as a feedstock for carbon applications was investigated using a semicontinuous supercritical propane (C3H8) extraction system. Experiments were carried out under different conditions to ascertain the effects of system pressure and temperature on the yields of extracted oils and the properties of residual pitches. The extraction residue obtained near 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 pressure was increased corresponding to the increased density of propane solvent. No difference in the yields and properties of residual pitches were observed at the experiments performed in the vicinity of the critical temperature of propane.