Study on deactivation of Co/ZrO2/SiO2 catalyst for Fischer-Tropsch synthesis

A Co/ZrO2/SiO2 catalyst active for synthesis of heavy hydrocarbons from syn gas was subjected to a stability test of 500 h on a laboratory scale. The c atalyst showed a considerable decrease in CO conversion, while the hydrocar bon distribution hardly changed with time on stream. The regeneration of de activated catalyst with H-2 at 673 K partially restored the activity. XRD, FT-IR and TGA identified a hydrated cobalt silicate species in the catalyst near the reactor outlet. Thus, the cause of deactivation was proposed main ly to be the formation of inactive hydrated silicate between Co metal and s ilica in presence of high partial pressure of water.