(44a) Increase ULSD Production with Customized ULSD Catalyst System Design

Increasing diesel demand coupled with the current poor margin environment is requiring the refining industry to discover and employ the most creative solutions to cost effectively maximize ultra-low-sulfur-diesel (ULSD) production from existing assets. Increased catalyst activity maximizes unit performance and ULSD production. However, using the highest activity catalyst is not always the best option as other factors such as H2 consumption and unit H2 supply can be limiting or expensive when not managed effectively. Customized catalyst systems for ULSD production can be designed to balance activity and H2 consumption. Recent developments have shown that customized systems utilizing CoMo and NiMo catalysts in various proportions and in various configurations (stacked beds and ?sandwich? beds) can yield unanticipated synergistic benefits when producing ULSD. Depending on the unique circumstances of each refiner, these synergistic benefits can be utilized to either process more ULSD feed, process a more difficult ULSD feed blend, or to extend cycle life. Pilot plant data are shown comparing the H2 consumption and activity of individual CoMo and NiMo catalysts to various CoMo/NiMo customized catalyst systems. A commercial example illustrating the use of a customized catalyst system in ULSD production is also presented. In this case, using a CoMo/NiMo/CoMo ?sandwich? catalyst system allowed the refiner to process a more difficult feed (higher refractory sulfur content, higher nitrogen, and higher feed final boiling point) without sacrificing catalyst cycle length or increasing H2 consumption.