The role of catalyst poisons during hydrodeoxygenation of renewable oils

Hydrodeoxygenation (HDO) activity of NiMo catalysts have been evaluated in the presence of catalyst poisons in bio-based feedstocks. An in-house synthesized NiMo/Al2O3 catalyst was placed in a refinery unit for biofuel production. Iron (Fe), phosphorus (P) and metals were identified as major contaminants. Calcination treatment was explored to recover the activity of spent catalysts. The effect of Fe, K and phospholipid containing P and Na on catalyst deactivation during hydrodeoxygenation of stearic acid was simulated at lab-scale. Fe caused the most deactivation where the highest feed concentration of the Fe compound resulted in 1480 ppm Fe deposited on the catalyst. Elemental distribution along the radial axis of spent catalysts indicated: Fe deposited only to a depth of 100 ?m irrespective of concentration while P and Na from phospholipid and K penetrated deeper in catalyst particles with a distribution profile that was found to be concentration dependent.

Automated summary

The HDO activity of NiMo catalysts in bio-based feedstocks was evaluated in the presence of catalyst poisons, with a focus on contaminants like Fe, P, and metals. Calcination treatment was studied for recovering the activity of spent catalysts. Fe was found to have the most deactivating effect, with Fe deposits found to a depth of 100 μm regardless of concentration.