Chemical studies of the SYNTHOIL process: catalyst deactivation

Technical Report · Tue Aug 01 04:00:00 EDT 1978

OSTI ID:6648731

Holloway, P H

The structure, composition, and activity of new and used coal liquefaction catalyst from SYNTHOIL reactors have been determined. The structure was characterized by optical and electron microscopy, surface area, pore size distribution, and buoyancy force measurements. The lateral and in-depth composition was studied with emission spectroscopy, electron microprobe, Rutherford backscattering, x-ray photoelectron, and Auger electron analyses. Catalytic activity was measured with product quality data and model compounds in a pulsed microflow reactor. These data show that one primary and three secondary deactivation mechanisms are operative in short term SYNTHOIL reactors. Coking is the dominant mechanism and significant coke deposition occurs very early in the SYNTHOIL process. Of the three secondary deactivation mechanisms, deposition of coke and coal minerals on the surface is the most obvious. However, no evidence was obtained to indicate that these crusts caused significant activity loss in these short-term experiments. Another mechanism is Fe and Ti penetration of the catalyst pellets, but again no activity loss was detectable. The fourth deactivation mechanism was adsorption of nitrogen compounds. These compounds plus other heteronuclear compounds cause both irreversible and reversible activity decreases during reactor start-up. These compounds make only a second order contribution to a time-dependent loss of catalytic activity. The secondary mechanisms may be more important in longer SYNTHOIL reactor runs. Techniques to regenerate used catalysts were considered, and it was shown that removal of the coke by ''burning'' in air was suitable. Techniques to prevent or reduce coking were also considered, especially during reactor start-up.

• Research Organization: Sandia Labs., Albuquerque, NM (USA)
• DOE Contract Number: EY-76-C-04-0789
• OSTI ID: 6648731
• Report Number(s): SAND-78-0056
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
AUGER ELECTRON SPECTROSCOPY
BACKSCATTERING
CATALYSTS
CHEMICAL ANALYSIS
COAL LIQUEFACTION
CRYSTAL STRUCTURE
DEACTIVATION
ELECTRON MICROPROBE ANALYSIS
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
EMISSION SPECTROSCOPY
LIQUEFACTION
MICROANALYSIS
MICROSCOPY
MICROSTRUCTURE
REGENERATION
SCATTERING
SPECTROSCOPY
SYNTHOIL PROCESS
THERMOCHEMICAL PROCESSES