Alternate use of heavy hydrotreatment and visbreaker naphthas by incorporation into diesel

In order to provide a solution for refineries having limited catalytic reforming capacity, a process scheme for incorporating most of the low octane heavy hydrotreatment and visbreaker naphthas into diesel is presented in this paper. This scheme involves blending the visbreaker naphtha with the feed to the diesel hydrotreatment units, processing this blend at the usual conditions for diesel hydrodesulfurization and changing the cut point in the diesel stabilizer.The proposed scheme was tested in a pilot plant, using blends of visbreaker naphtha and straight run gas oil as feedstock. The proportion of visbreaker naphtha was selected according to the production of this naphtha and of straight run gas oil in a typical refinery. The hydrotreated product was stabilized at different cut points and a target cut point was selected for maximum diesel production, meeting all the product specifications.This scheme was applied at a refinery having one visbreaking unit and two diesel hydrotreatment units, resulting in an increase of 6-7% in diesel production.