FORMATION OF NITROGEN-COMPOUNDS FROM NITROGEN-CONTAINING RINGS DURINGOXIDATIVE REGENERATION OF SPENT HYDROPROCESSING CATALYSTS

Commercial CoMo and NiMo catalysts in an oxidic and sulfided form and a gamma-alumina were deposited with pyrrole, pyridine, and quinoline. The deposited catalysts and two spent hydroprocessing catalysts were p yrolyzed and oxidized under conditions typical of regeneration of hydr oprocessing catalysts. The formation of NH3 and HCN, as well as select ed cases of N2O and NO, was monitored during the experiments. NH3 and HCN were formed during pyrolysis of pyrrole-deposited catalysts wherea s only NH3 was formed during that of pyridine- and quinoline-deposited catalysts. For all deposited catalysts, both NH3 and HCN were formed during temperature programmed oxidation in 2% O-2. For spent catalysts , a small amount of N2O was formed in 2 and 4% O-2. For pyrrole-deposi ted catalysts, large yields of N2O were formed in 4% O-2. Under the sa me conditions, N2O yields for pyridine- and quinoline-deposited cataly sts were very small.