ISSN:
1572-9028
Keywords:
Fischer-Tropsch synthesis
;
cobalt catalysts
;
eggshell catalysts
;
diffusional restrictions
;
CO hydrogenation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract CO diffusional restrictions decrease C5+ synthesis rates and selectivity within large (1–3 mm) catalyst pellets often required in Fischer-Tropsch (FT) synthesis reactors. Eggshell catalysts, where Co is located preferentially near outer pellet surfaces, reduce the severity of these transport restrictions and lead to higher synthesis rates and C5+ selectivity. Maximum C5+ selectivities occur on catalysts with intermediate shell thickness, within which transport restrictions limit the removal of reactive olefins but not the arrival of reactants at catalytic sites. A new synthetic technique leads to sharp distributions of active sites near outer pellet surfaces by controlling the rate of imbibition of cobalt nitrate melts. Also, slow reduction of the impregnated salt leads to moderate Co dispersions (0.05–0.10) even at high local Co loadings present within shell regions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01491952
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