Several commercial processes have been successfully used for upgrading heavy petroleum feeds containing less than 300 ppm of V + Ni. For problematic petroleum feeds, metal content exceeds this level and may approach 1000 ppm of V + Ni. Frequently, the upgrading battery is located in remote locations in the proximity of the heavy crude producing wells. In this case, the objective of upgrading is a syncrude suitable for pipelining. The complexity of upgrading increases with increasing content of metals, resins, and asphaltenes. The database of processing parameters has to be established for selecting optimal upgrading schemes, e.g., catalytic versus noncatalytic routes. From a processing point of view, the information on the yield of syncrude, steam, and electricity requirements, as well as hydrogen and catalyst consumption, are of primary interest. The parameters determining the environmental impact on the upgrading schemes have to be considered as well. The processes suitable for upgrading problematic feeds under evaluation include catalytic hydroprocessing, slurry bed hydrocracking, and coking. Various combinations of these processes have been used as well. Deasphalting combined with catalytic processes may be an attractive route providing that the rejected asphalt can be efficiently utilized on site. Lowered emissions can be achieved by utilizing asphalt and other residues from upgrading on gasification island for production of hydrogen, carbon dioxide, steam, and electricity. Compared with combustion, an integrated gasification-combined cycle operates at higher overall thermal efficiency with all emissions being significantly lower.
