New Trends in Hydroprocessing Spent Catalysts Utilization

The distillate of crude oil is an essential step in the petroleum refining practice. The yield and properties produced distillates depend on the properties of crude oil, distillation conditions and the type of distillation column. Primary distillates are subjected to an additional treatment to meet the environmental requirements and the performance of produced fuels. The schematics of a typical refinery operation processing a conventional crude shown in Fig. 1 lists four catalytic processes, i.e. reforming, hydrocracking, hydrotreating, catalytic cracking and alkylation. The residue from atmospheric distillation may be subjected to additional distillation under a vacuum to obtain valuable lubricant fractions which also require catalytic hydrotreatment. Noneconventional refineries can process heavy oils and distillation residues. In this case, the catalytic hydro cracking of the heavy feed is usually the first step, followed by hydrotreating of the synthetic distillates. For the purpose of this review, the hydroprocessing will refer to both hydrocracking and hydrotreating. Light hydrocarbon which is byproducts of several refineries can converted to high octane fractions by catalytic alkylation and polymerization.