Combination residue hydrodesulfurization and thermal cracking process

摘要

A process comprising passing a residual oil through a plurality of hydrodesulfurization stages in series to produce a relatively low sulfur hydrodesulfurizer residual oil effluent. A portion of desulfurized oil flowing between stages is passed through a thermal cracking zone containing a packed bed of inert solids to produce middle distillates and a cracked residual oil which is relatively high in sulfur but which contains less than 7 weight percent pentane insolubles. Because of its low aromaticity, the relatively high sulfur cracked residual oil is compatible for blending with the relatively low sulfur hydrodesulfurizer residual oil effluent.