Three-catalyst process for the hydrotreating of heavy hydrocarbon streams

Abstract

There is disclosed a process for hydrotreating a heavy hydrocarbon stream containing metals, asphaltenes, nitrogen compounds, and sulfur compounds to reduce the contents of these contaminants. The process comprises contacting said stream in the presence of hydrogen and under suitable hydrotreating conditions in sequence with a first catalyst in a first reaction zone, a second catalyst in a second reaction zone, and a third catalyst in a third reaction zone. The first catalyst comprises a Group VIB metal and/or a Group VIII metal on a porous inorganic oxide support; the second catalyst consists essentially of at least one hydrogenation metal selected from Group VIB deposed on a support material comprising alumina; and the third catalyst comprises a hydrogenating component comprising molybdenum, chromium, and cobalt on a large-pore, catalytically-active alumina. Each catalyst has specific physical properties.