When high activity catalysts are loaded at the top of a commercial hydrotreater, the reactive species present in the feed can be converted too quickly, beyond the rate that hydrogen can be replenished. This can create areas of localized hydrogen starvation which promotes polymerization and coke formation resulting in shorter than expected cycles.

UDEC has a complete line of active Grading Materials that gradually convert reactive species and control the rate of hydrogenation to reduce fouling.