Demetallization of asphaltenes: Thermal and catalytic effects with small-pore catalysts
- Oklahoma State Univ., Stillwater, OK (United States)
- Phillips Petroleum Co., Bartlesville, OK (United States)
Residual oil hydrotreating has become an important front end process in commercial oil upgrading schemes because of tighter environmental regulations and a continuing trend toward processing heavier crudes. At Phillips Petroleum, residual oil hydrotreating pretreates feed for heavy oil cracking (HOC) by removing sulfur, a pollutant in the HOC stack gas, and metals such as nickel and vanadium, which adversely affect the cracking catalyst and gasoline yield in the HOC. Metals in residual oil are found almost exclusively in the resin and asphaltene fractions. Research has showed that metals in the resin fraction react more rapidly than metals in the asphaltene fraction. The hydrodemetallization (HDM) reaction is known to be diffusion limited and the larger molecular size of the asphaltene molecules may explain the slower reaction rates. Richardson and Alley and Asaoka, et al. have shown a reduction in asphaltene molecular weights with thermal and catalytic processing. Reynolds and Biggs demonstrated shifts in vanadium size distributions from thermally and catalytically treated residual. Recently Savage and Javanmaridian showed theoretically that reduction in molecular sizes external to catalyst pellets increases the reaction rate by as much as the inverse of the effectiveness factor. This work attempts to extend information on how metals are removed from asphaltenes and the interaction with small-pore catalysts generally found at the back end of residual oil hydrotreaters, where they are protected from deactivation by metal deposition. The small-pore catalysts are generally high in hydrodesulfurization (HDS) activity and generally restrict the large asphaltene molecules from entering their pores and depositing metals.
- OSTI ID:
- 7067910
- Report Number(s):
- CONF-900802--
- Journal Information:
- American Chemical Society, Division of Petroleum Chemistry, Preprints; (United States), Journal Name: American Chemical Society, Division of Petroleum Chemistry, Preprints; (United States) Vol. 35:4; ISSN 0569-3799; ISSN ACPCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020400* -- Petroleum-- Processing
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ASPHALTENES
ASPHALTS
BITUMENS
CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
DEMETALLIZATION
DESULFURIZATION
DIFFUSION
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
KINETICS
METALS
MICROSTRUCTURE
MOLECULAR WEIGHT
MOLYBDENUM
NICKEL
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PETROLEUM
PETROLEUM FRACTIONS
PETROLEUM RESIDUES
POROSITY
REACTION KINETICS
SEPARATION PROCESSES
TAR
TRANSITION ELEMENTS
VANADIUM