Cascaded Hydrotreating Process Reduces Refiners' Costs

As refiners produce gasoline and diesel products to clean fuels specifications, severe hydrotreating is required of several streams.

Many refineries have both gas oil (FCC feed) hydrotreaters, and diesel hydrotreaters. It is possible to design a hydrotreater reactor scheme to hydrotreat gas oil and diesel streams in series, in a single reactor loop. By using this cascaded hydrotreater scheme, capital costs and operating costs will be less than for two separate units processing these streams.

Fluor has been awarded a U.S. patent (#7,238,274, Combined Hydrotreating Process, Turner, issued July 3, 2007) for a processing scheme that hydrotreats a heavy hydrocarbon stream and a lighter hydrocarbon stream in series.

The details of the process schme, and the advantages and disadvantages of the design, are presented in this paper.