Investigating the effect of calcination repetitions on the lifetime of Co/γ-Al2O3 catalysts in Fischer–Tropsch synthesis utilising the precursor's solution affinities

Abstract

Cobalt-based catalysts were prepared on different alumina supports, and their behaviour for different Fischer–Tropsch synthesis (FTS) conditions assessed. Although Co/γ-Al2O3 is a well-known FTS catalyst, its durability ought to be improved to make the industrial process economically feasible. Here calcination repetitions effects on the catalyst lifetime were examined utilising reactor tests and characterisation techniques including XRD, TPR, ICP and N2 porosimetry. Results revealed that fewer calcination repetitions improved catalyst activity and selectivity. Based upon the XRD results, these findings appeared to be due to the improved size of cobalt crystals on the pore surfaces. These translated into the affinity of the precursor solution towards different surfaces which were ranked in this research. Catalyst characterisations demonstrated that fewer calcination repetitions yielded a larger surface area and pore volume due to less sintering. TPR analysis indicated that fewer calcination repetitions resulted in improved reduction, hence more available surface cobalt for reaction.