Study on stability of Co/ZrO2/SiO2 catalyst for F-T synthesis

Co/ZrO2/SiO2 catalyst active for synthesis of heavy hydrocarbons from syngas was subjected to stability test of 500 hours on a laboratory scale. The catalyst showed a considerable decrease in CO conversion while the hydrocarbon distribution hardly changed with time on stream. The regeneration of deactivated catalyst with H2 at 673K partially restored the activity. XRD, FT-IR and TPR identified a hydrated cobalt silicate species in catalyst near outlet of reactor. Thus, the cause of permanent deactivation was proposed mainly to be formation of inactive hydrated silicate between metallic Co and silica in the presence of high partial pressure of water.