Characterization of Petroleum Residues with Varying Cutting Depth and Corresponding Vacuum Distillates Derived from Laboratory Deep-Vacuum Fractionation of Unconventional Heavy Oil for an Instructive Utilization Guideline

Petroleum residues with varying cutting depth and corresponding vacuum distillates have been prepared from laboratory deep-vacuum fractionation using unconventional heavy oil (UHO) originated from Venezuela first. They are then sequentially characterized by general analysis, process analysis, and pyrolysis analysis with thermogravimetric analysis (TGA), derivative thermogravimetric analysis (DTG), and differential scanning calorimetry (DSC). Results indicate that a greater increase in distillates recovery would be expected in the case of UHO than that of other referenced crudes under the same cut temperature and stand a good chance to make refineries involved with UHO get comfort by partially offsetting the shortage of light distillates. From the-view of structural composition characteristics, cuts, even the ones with high cut temperature, have a high chance of cracking into compounds with lower molecular weight during conversion. Notably, in the, case of +565 degrees C petroleum residue (R5), except for the endothermic effect, an exothermic effect is also shown in the DSC profile, which means that the thermodynamic characteristics of petroleum residues would change from endothermic to exothermic as the thermal process exceeds some conversion point, at which coke yield is 45.8 wt % in the study.