Usually there will be two gas oil side streams, a light gas oil side stream and belowthis take off a heavy gas oil side stream is withdrawn. Both these side—streams are steam stripped to meet their respective flash point specification (usually 150?F minimum). The lighter side stream (cut of about 480–610?F on crude) is the principle precursor for the automotive diesel grade finished product.
This side stream is desulfurized to meet the diesel sulfur specification in a hydrotreater . The lower gas oil stream is really a guard stream to correct the diesel distillation end point. This heavy gas oil may also be hydro-desulfurized and routed to either the fuel oil pool (as a precursor for marine diesel for example) or to a finished heating oil product from the gas oil pool.