Surface analysis of a deactivated coal liquifaction catalyst
Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (ESCA) have been used to study new and used coal liquefaction catalysts. By examining Harshaw 0402T cobalt and molybdenum oxide hydrodesulfurization catalyst with these and other analytical techniques, the mechanisms of deactivation have been illustrated. AES data showed that Fe and Ti penetrated into the catalyst pellet to depths of 100 ..mu..m, and that Fe, Ti, and other elements from the natural minerals in coal were deposited on the surface. These data are consistent with deactivation by (1) covering of active interior catalyst sites by Fe and Ti deposits, and (2) deposition of mineral matter as a surface crust. The detection of nitrogen by AES is consistent with a third deactivation mechanism: (3) adsorption of heterocyclic compounds. AES data demonstrate that C concentrations occurred near the outer surface of the pellet and that C concentrations on pellets from the inlet were lower than those from the middle or outlet of the reactor. ESCA data also show that catalytic sites were covered with C deposits, and that the hydrocracking sites were more deactivated than were the heteroatom removal sites. Thus a fourth, and most important, deactivation mechanism was (4) deposition of carbon in the catalyst pellet (coking).
- Research Organization:
- Sandia Labs., Albuquerque, N.Mex. (USA)
- DOE Contract Number:
- EY-76-C-04-0789
- OSTI ID:
- 5365045
- Report Number(s):
- SAND-77-1389
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
ADSORPTION
AUGER ELECTRON SPECTROSCOPY
CARBON
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL LIQUEFACTION
COBALT COMPOUNDS
COBALT OXIDES
DEACTIVATION
DEPOSITION
DESULFURIZATION
ELECTRON SPECTROSCOPY
ELEMENTS
HETEROCYCLIC COMPOUNDS
HYDROGENATION
LIQUEFACTION
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SORPTION
SPECTROSCOPY
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS