| Abstract
| - Spray drying has been recently used by this research team in the preparation of Fe Fischer−Tropsch catalysts with higher attrition resistance for use in slurry bubble column reactors. Inthe first paper in this series, the effects of the type, concentration, and network structure ofSiO2 on the attrition resistance of two series of spray-dried Fe catalysts in their calcined statewere explored and the dependence of catalyst attrition resistance on catalyst particle densitywas discussed. As a continuation of our previous effort, the effect of carburization on catalystattrition resistance was studied and is presented in this paper. After carburization, the majoritycomponent of the catalysts, hematite (Fe2O3), was converted to iron carbides, mostly χ-carbide(Fe2C5). Breakage of individual catalyst particles and fines formation, which can be consideredas evidence of chemical attrition, was only observed during carburization of the catalyst withlow SiO2 concentration <9 wt %. With an increase in the total concentration of SiO2, suchchemical attrition during the Fe phase change appeared to be eliminated or negligible exceptfor the breakup of large agglomerates during carburization. There were, generally, significantdecreases in the Brunauer−Emmett−Teller surface areas and average particle sizes of thecatalysts upon carburization. Surprisingly, carburization of these Fe catalysts did not weakenthe particle structures with regards to physical attrition. In fact, depending on catalystcomposition, the overall attrition resistances of the carburized catalysts measured using a jetcup system were similar to or better than those of the same catalysts in their calcined form.However, any seeming improvement in attrition resistance is suggested to be related mainly tothe increase in catalyst particle density (related to catalyst inner structure) after carburization.
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