Hs. Joo et Ja. Guin, ACTIVITY OF NOBLE METAL-PROMOTED HYDROPROCESSING CATALYSTS FOR PYRIDINE HDN AND NAPHTHALENE HYDROGENATION, Fuel processing technology, 49(1-3), 1996, pp. 137-155
An important step in the upgrading of coal and coal-waste coprocessing
liquids is the removal of heteroatoms, particularly nitrogen, which t
end to poison the downstream cracking operations required to lower boi
ling points to the transportation fuels range. This requirement has mo
tivated research to improve the activity of current hydroprocessing ca
talysts. In this regard we have examined the effects of Pt, Ru, and Ir
promotion on three commercial Al2O3-supported catalysts (NiMo, CoMo,
and NiW) using the model compounds, pyridine and naphthalene, to inves
tigate hydrodenitrogenation and ring hydrogenation reactions, respecti
vely. For pyridine hydrodenitrogenation (HDN), the activity of the sul
fided catalysts was better than that of the oxide forms. For sulfided
forms of NiMo, all noble metals tested improved the HDN activity. The
activity of CoMo was improved by Pt and Ir while NiW was not improved
by any noble metals promotion. For ring hydrogenation (HYD) of naphtha
lene, the Pt-promoted catalysts were more active than the original cat
alysts in the oxide forms, while the activities of both catalysts were
similar after sulfidation. However for ring HYD in the presence of N,
the Pt-promoted catalysts exhibited a distinct advantage.