Characterization of fresh, deactivated, and regenerated commercial hydrocracking catalysts using piperidine hydrogenolysis as a probe reaction
The hydrogenolysis of piperidine over a series of fresh, commercially-deactivated, and regenerated cobalt molybdate zeolite-containing hydrocracking catalysts was studied in order to investigate the possible mutual interactions of the metallic and acidic catalyst functions under reaction conditions, and to determine the effects of deactivation and regeneration on the performance of these catalysts. The fresh and regenerated catalysts were sulfided prior to reaction, while the deactivated catalysts were not presulfided. The reactions were carried out in a continuous flow fixed-bed reactor system operating in integral model. Catalyst characterization studies were conducted at temperatures ranging from 281 to 321 C and hydrogen partial pressures of 11.21 to 16.04 atm. The product distribution revealed that the predominant reactions were those changing piperidine to other types of nitrogen compounds and both catalyst functions were active simultaneously. To offset effects of catalyst deactivation during the experiments, the conversion data were extrapolated to zero time on stream. The kinetics study over the fresh catalyst indicated that the deactivation rate and coke formation during the reactions increased with increasing temperature and initial piperidine concentration. The regenerated catalysts exhibited lower metallic function activity in some reactions compared to the fresh sample. The primary cause of the loss of metallic function activity for the deactivated catalysts was sulfur deposition on the surface. The major causes of deactivation for the acidic function were coke deposition and decrease in the zeolite unit. An inverse relationship between catalyst deactivation rate and unit cell size was observed for both catalyst functions.
- Research Organization:
- Northwestern Univ., Evanston, IL (USA)
- OSTI ID:
- 7032919
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COBALT
CATALYTIC EFFECTS
MOLYBDENUM COMPOUNDS
PIPERIDINES
DEHYDROGENATION
ZEOLITES
CATALYSTS
CHEMICAL REACTION YIELD
CHEMICAL REACTORS
COKE
DEACTIVATION
DEPOSITION
HYDROCRACKING
KINETIC EQUATIONS
PERFORMANCE TESTING
QUANTITY RATIO
REGENERATION
SULFIDATION
SULFUR
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
AMINES
AZINES
CHEMICAL REACTIONS
CRACKING
DECOMPOSITION
ELEMENTS
EQUATIONS
HETEROCYCLIC COMPOUNDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
METALS
MINERALS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
PYROLYSIS
REFRACTORY METAL COMPOUNDS
TESTING
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YIELDS
020400* - Petroleum- Processing