Long term stable Co-based catalysts for Sabatier reaction under changing feed loads

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Energy from renewable sources can be stored in the form of hydrogen. However, stockpiling hydrogen has many disadvantages that can be circumvented transforming it into methane using the so called Sabatier reaction. At stationary conditions this catalytic reaction is already well understood and frequently applied in bundled tubular reactors. However, since the renewable energy sources are often fluctuating and so is the hydrogen supply and therefore the feed loads for the Sabatier reaction. This leads to temperature hot spots in cases of decreasing volume flows due to insufficient heat management capabilities especially in industrially applied 25 mm reactor tubes. This can result in a thermal deactivation of the catalysts due to sintering and reaction of catalytic components and surface area loss. The goal of the present project is the design of cobalt-based catalysts that can sustain high activity under changing loads over long running times. One aim is to determine the influence of catalyst doping at the atom and nanometer scale with respect to time and spatial changes in the catalyst layer during dynamic feed loads. In order to synthesise such Co-based catalyst libraries with high activity, selectivity and stability, the flame spray pyrolysis technique will be employed. To this aim an asymmetrical double flame configuration will be realized and investigated. This technique will allow a large variety of independent catalyst doping’s and catalyst / support designs using a single high temperature synthesis process. Another aim is to determine the time and spatial changes within a tubular reactor under fluctuating feed loads. To this aim operando MRI methods will be developed and employed that can locally measure feed and product streams and temperatures up to wall temperatures of 350 °C.