Iron-induced deactivation of Raney and supported nickel methanation catalysts. Annual progress report, September 15, 1978-September 15, 1980

It was concluded that: (1) the decreasing activity of Ni catalyst for methanation is caused by both catalyst sintering and surface sites blocking, probably by carbon deposition; and (2) the increases in particle size are mainly attributed to the formation and subsequent decomposition of Ni(CO)/sub 4/. The local overheating contributes, if any, only minor portions to the observed catalyst sintering. In the extreme cases, such a process can cause massive metal transportation down the catalyst bed. In view of the thermodynamics of carbon deposition via Boudouard reaction and formation of Ni(CO)/sub 4/, the operating temperatures for future kinetic studies should be kept higher than, say, 523 K. Also, the CO exposure times will be kept as short as possible to avoid complication induced by Ni(CO)/sub 4/. The equipment for high pressure Moessbauer spectroscopy will be ready to go in the near future.