Piperidine hydrogenolysis on a commercial hydrocracking catalyst. II. The effects of initial piperidine concentration, temperature, catalyst presulfidation, and hydrogen partial pressure on catalyst activity, deactivation, and coke formation

Journal Article · Fri May 01 00:00:00 EDT 1992 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(92)90266-K· OSTI ID:6938989

Hadjiloizou, G C; Butt, J B; Dranoff, J S ^[1]

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1. Northwestern Univ., Evanston, IL (United States)

The formation of coke in the piperidine hydrogenolysis reaction over a fresh sulfided hydrocracking catalyst was examined at temperatures ranging from 281 to 321 C, hydrogen partial pressures of 11.2 to 15.9 atm (1.1 to 1.6 MPa), and initial concentrations of piperidine of 3.94 [times] 10[sup [minus]3] to 11.84 [times] 10[sup [minus]3]g mol/liter using elemental analysis, [sup 13]C NMR spectroscopy, and ESCA. The results indicated that most of the coke present on the catalyst after 17 h on stream was deposited in the initial 90 min of the reaction. Coke formation and hence catalyst deactivation were found to increase with both reaction temperature and initial concentration of piperidine. Reducing the catalyst instead of sulfiding it had no effect on the final coke content. Nitrogen was found to be present on the catalyst surface after reaction indicating that nitrogen-containing compound were participating in the formation of coke. The H/C ratio of the coke decreased very slowly with reaction time and was invariant to changes in temperature, initial concentration of piperidine, or catlayst pretreatment method. Comparing the activity of reduced versus sulfided fresh catalysts in the hydrogenolysis of piperidine, it was found that under the present conditions, catalyst presulfidation increased the activity of the metallic catalyst function and decreased the rate of catalyst deactivation. Furthermore, decreasing the partial pressure of hydrogen resulted in an activity decrease of the metallic catalyst function and had a negative effect on the overall catalyst activity maintenance. The intrinsic activity of the acidic catalyst function was not affected by the change in hydrogen partial pressure.

• OSTI ID: 6938989
• Journal Information: Journal of Catalysis; (United States), Vol. 135:1; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
CATALYSTS
DEACTIVATION
PIPERIDINES
HYDROGENATION
CARBON 13
COKE
DEPOSITION
ELECTRON SPECTROSCOPY
HYDROGEN
MEDIUM PRESSURE
NUCLEAR MAGNETIC RESONANCE
PARTIAL PRESSURE
QUANTITY RATIO
REDUCTION
SULFIDATION
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
AMINES
AZINES
CARBON ISOTOPES
CHEMICAL REACTIONS
ELEMENTS
EVEN-ODD NUCLEI
HETEROCYCLIC COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NONMETALS
NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
RESONANCE
SPECTROSCOPY
STABLE ISOTOPES
TEMPERATURE RANGE
020400* - Petroleum- Processing