Nickel deactivation during gasification reactions

Changes in the partitioning of total surface area of nickel catalyst particles between the metal-carbon interface and the metal-gas interface were studied as catalyst deactivation proceeded. Previously reported studies of this repartitioning used catalyst characterization after cooling from reaction temperature to some lower temperature. In the present study the extent of water-gas shift reaction during the gasification was used to probe changes in the metal-gas interfacial area without cooling the sample. The results obtained were consistent with those based upon catalyst characterization after cooling and suggest the cooling procedure used does not cause changes in the catalyst system. When. catalytic gasification rates were renormalized using the metal-gas interfacial area the rate of reaction was still found to vary with the time on stream, though not nearly as extensively as before the renormalization. The origin of these variations is discussed.