Deactivation of a precipitated iron Fischer–Tropsch catalyst—A pilot plant study

Fischer–Tropsch Synthesis: Deactivation as a Function of Potassium Promoter Loading for Precipitated Iron Catalyst

“…Deactivation of the iron catalysts may be explained by the following four mechanisms, which have been described in the literature. Those are: (1) active iron carbide phases are gradually oxidized to magnetite (Fe 3 O 4 ), which is relatively inactive for FTS [28,49,50]; (2) deposition of inactive carbonaceous compounds takes place on the surface of the catalyst, thereby limiting the contact between reactant gases and the catalytically active phase [17,29,[51][52][53]; (3) sintering, which is the loss of catalytic surface area due to ripening or migration and coalescence of iron phases [54,55]; and (4) poisoning and deactivation by sulfur compounds, which are typically present in most syngas feeds. In the present study, the same syngas was used from two pure H 2 and CO tube trailers and so the possibility of poisoning by sulfur compounds was ruled out.…”

Middle distillates production via Fischer–Tropsch synthesis with integrated upgrading under supercritical conditions

“…Another possibility is that during the startup period of the FTS reaction, a tremendous amount of reaction heat is released once the FTS reaction conditions (temperature and pressure) are achieved since the FTS reactions are so highly exothermic. In gas phase operation, the local heat removal rate may not be sufficient such that catalytic hot spots can be generated which would inherently lead to catalyst sintering and fouling (deposition of inactive carbonaceous compounds such as amorphous carbon, graphitic carbon, coke) and thus loss of surface area and active catalyst sites . As a result, catalyst deactivation may have occurred due to a loss of catalyst active sites before steady‐state operation was achieved in GP‐FT and GP‐FTOC.…”

Removal of hydrogen sulfide from a steam-hydrogasifier product gas by zinc oxide sorbent: Effect of non-steam gas components

“…Depending on the source of the carbonaceous materials which are diverse from biomass, coal, and solid wastes to their mixtures, the steam-hydrogasifier product gas is usually contaminated by sulfur compounds, mostly as hydrogen sulfide, in varying concentrations. Removal of the sulfur contaminants is required to protect the catalysts used for downstream reaction such as steam-methane reforming or Fischer-Tropsch synthesis from being deactivated, let alone to protect the hardware from being corroded [3,4].…”