Development of an Attrition Resistant Fischer–Tropsch Catalyst for Slurry Operation

Abstract

Resistance towards attrition, sufficient activity at end-of-run and high selectivity to desired products are some of the requirements for a slurry Fischer-Tropsch catalyst. We have found that modifying an alumina support by 2-valent metals, including magnesium, nickel and zinc, followed by high temperature firing, results in superior mechanical and 'chemical attrition' (dissolution) resistance of the catalyst. Further, a sufficiently high surface area is being stabilized. The catalyst performance has been verified in a long term test in a semi-commercial plant, including very good wax separation and high wax purity. Combined with appropriate process conditions, stable longterm operation of the catalyst is secured.

Deactivation and Regeneration of Commercial Type Fischer-Tropsch Co-Catalysts—A Mini-Review

“…Upon re-reduction metal crystallites may agglomerate depending on the initial spatial distribution on the catalyst support. That cobalt distribution can vary significantly with catalyst preparation procedure is illustrated in Figure 2 for a Co/Re/γ-alumina catalyst [43]. Cobalt dispersions are comparable, but we see that the distribution of clusters of the oxide varies significantly.…”

“…It appears that Sasol focuses more on avoiding chemical attack on their γ-alumina based support [40], whereas Statoil/GTL.F1 [41], IFP/ENI/Axens [28], and probably Exxon [42], have developed more mechanically robust slurry catalysts.…”

“…Statoil/GTL.F1 have disclosed deactivation profiles at several conferences for their attrition resistant catalyst of Co/Re/aluminate spinel catalyst. In a CSTR slurry reactor test over 3000 h the temperature was adjusted regularly, typically in 2-3 weeks intervals, to keep conversion reasonable constant [43]. Somewhat surprisingly, temperature was decreased from 222 °C to 215 °C during the operation meaning that the catalyst activity increased regularly.…”

“…Regeneration may re-disperse cobalt, possibly even to a level higher than for a freshly reduced catalyst [70]. A promoted cobalt catalyst on a spinel support was subjected to an extended run in a slurry-bubble column reactor as described by Schanke et al [14].…”

“…Catalyst activity before and after oxidation of carbon deposits of a catalyst used in a slurry bubble column reactor (data from ref. [70]). …”