EVALUATION OF FEEDSTOCKS FOR DEVELOPMENT OF HYDROCRACKING CATALYSTS FOR HEAVY OIL

A number of feedstocks namely Arab Light atmospheric residue (ALAR), Arab Heavy atmospheric residue (AHAR), vacuum gas oil (VGO) and hydrotreated vacuum gas oil (HT-VGO), were evaluated for their physical and chemical characteristics. The characterization results of the feedstocks show the complex nature and composition of both residues and gas oils. The distillation results showed that about 50 weight percent of Arab Light crude consists of atmospheric residue. The elemental analysis of the ALAR showed that high amount of carbon, sulfur and nitrogen is present along with heavy metals such as nickel and vanadium. In case of Arab Heavy crude oil, the atmospheric residue is even higher, that is 57 percent and contains higher amount of metals along with more carbon, sulfur and nitrogen contents. The determination of hydrocarbon types by HPLC exhibited that ALAR contains higher amount of saturates compared to AHAR but less amount of aromatics, polars and asphaltenes. ALAR was found to have 55% saturates, 27% aromatics, 12% polars and 6% asphaltenes while AHAR has 30% saturates, 42% aromatics, 18% polars and 10% asphaltenes. Molecular weight determination indicated that the molecular weight of ALAR was determined to be 511 compared to 595 for AHAR. ALAR being lighter, showed 54% distillation at 547°C while AHAR exhibited 45% distillation at 543°C. VGO was found to have 13% saturates, 68% aromatics and 19% polars while HT-VGO had 29% saturates, 63% aromatics and 8% polars. VGO was found to have high IBP and FBP compared to HT-VGO. On the basis of the characterization data, VGO was selected to be use with catalysts containing high pore size supports such as alumina, silica alumina and clay while HT-VGO was selected as feedstock for performance evaluation of zeolite based catalysts. ALAR and AHAR will be utilized in the later stages of the catalysts development work.