ABSTRACT
Aromatics saturation over hydrotreating catalysts has been investigated by processing a synthetic feedstock to which naphthalene, biphenyl, tetralin, and cyclohexylbenzene have been added as model aromatic compounds.
The saturation reactions were successfully correlated with a kinetic model of consecutive first order reactions. The rates of saturation of the di-aromatics, naphthalene and biphenyl, were approximately 5-40 times faster than the rate of saturation of the mono-aromatics, tetralin and cyclohexylbenzene.
The nature of the di-aromatic is a significant determinant of its reactivity for saturation. The rate of saturation of naphthalene is 10 - 20 times faster than the rate of saturation of biphenyl. The two mono-aromatics, tetralin and cyclohexylbenzene, exhibited nearly identical reactivities for saturation.
An investigation of the effect of organo-nitrogen compounds on saturation activity revealed a very severe poisoning and attenuation of saturation activity. Since activity was recoverable upon the removal of the poisoning agent the chemical effect was conjectured to be due to adsorption of the poison on the active sites of the catalyst. The adsorption constants were determined for three model nitrogen compounds - quinoline, indole, and tert-butylamine. The poisoning action of an organo-nitrogen compound was found to be dependent on both basicity and chemical structure.254
