Preparational factors and characterization of Ni-Mo/Al sub 2 O sub 3 hydrotreating catalysts
The purpose of this work is to (1) provide a better fundamental understanding of the relationships between preparation and structure of Ni-Mo/Al{sub 2}O{sub 3} catalysts and process performance, (2) develop simple characterization tests useful in quality control and in screening potential exploratory catalysts, and (3) establish improved design principles. Commercial production routes were used to produce a catalysts series with systematic variations in both MoO{sub 3} (10-20 wt.%) and NiO (0-7 wt.%) contents and calcination temperature (300-600 C). Catalysts characterization was accomplished through combined magnetic susceptibility, acid extraction, nitric oxide chemisorption, infrared spectroscopy, and thiophene HDS kinetic measurements. Several oxidic Ni phases were identified: bulk NiO, surface or subsurface NiAl{sub 2}O{sub 4}, and octahedral and tetrahedral Ni associated with Mo. Tetrahedral Ni was found to promote both HDS and hydrogenation activities of two types of sites. A sulfided catalyst structural model describing all identified Ni and Mo species and structures was proposed. Tetrahedral Ni occupies edge substitutional positions for Mo on the periphery of NoS{sub 2}-like domains, anchored via oxide bonds to the alumina support. Improved hydrotreating catalysts are believed possible through incorporation of phosphorus pentaoxide, P{sub 2}O{sub 5}, during catalyst preparation. The large phosphate anions force restricted growth of Mo domains, creating small, multilayered Mo structures containing more edge sites for tetrahedral Ni occupation. Magnetic susceptibility, which directly measures tetrahedral Ni content, is recommended as a useful characterization for screening catalysts.
- Research Organization:
- Houston Univ., TX (USA)
- OSTI ID:
- 7025779
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020400* -- Petroleum-- Processing
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CALCINATION
CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHEMISORPTION
CONTROL
CORRELATIONS
CRYSTAL STRUCTURE
DECOMPOSITION
DESULFURIZATION
EXTRACTION
HETEROCYCLIC COMPOUNDS
HYDROGENATION
INFRARED SPECTRA
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MEASURING METHODS
MICROSTRUCTURE
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
NICKEL COMPOUNDS
NICKEL OXIDES
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PHOSPHORUS OXIDES
PHYSICAL PROPERTIES
PROCESSING
PROMOTERS
PYROLYSIS
QUALITY CONTROL
RECOMMENDATIONS
REFINING
REFRACTORY METAL COMPOUNDS
REGENERATION
SEPARATION PROCESSES
SOLVENT EXTRACTION
SORPTION
SPECTRA
SPECTROSCOPY
SURFACE PROPERTIES
SYNTHESIS
THERMOCHEMICAL PROCESSES
THIOPHENE
TRANSITION ELEMENT COMPOUNDS