(130a) Catalyst Selection for Ultra Low Sulfur Diesel Operations: Activity and H2 Consumption Considerations

Ultra Low Sulfur Diesel (ULSD) operations target significantly lower product sulfur levels, typically < 10 wppm, than current diesel hydrotreating operations. State-of-the-art catalysts are required to achieve reasonable cycle lengths in ULSD operations. ULSD production results in significantly higher H2 consumption than is observed in LSD production (product S < 500 wppm). Maximizing catalyst activity and balancing H2 consumption with unit H2 supply capabilities are critical considerations in ULSD catalyst selection. This paper discusses catalyst selection and application in ULSD production. Pilot plant data are presented comparing high activity STARS CoMo and STARS NiMo catalysts to elucidate the impact of catalyst selection, process conditions, and process severity on performance (hydrodesulfurization, hydrodenitrogenation, aromatics saturation, color improvement, H2 consumption). A ULSD catalyst system optimization study of STARS CoMo and STARS CoMo/Nebula demonstrates that proper catalyst system design can achieve improved catalyst activity while managing H2 consumption and maintaining catalyst stability. Commercial data illustrating the impact of catalyst system design on H2 consumption/unit H2 supply balance and catalyst deactivation/cycle length are discussed. Catalyst selection guidelines for ULSD operations are presented.