Rational design of a methanation reactor by neutron imaging

The reaction conditions in industrial scale chemical reactors can differ markedly from the ones in a small laboratory scale reactor. The differences are both conceptual and practical, and can at best be analysed by studying a full reactor, which requires an analytical method capable of quantifying the distribution of reactants and products in a running reactor. For this, we introduce non-destructive <i>operando</i> neutron imaging in combination with modelling. As a representative reaction, we studied the hydrogenation of carbon dioxide to methane selected due to the large neutron cross-section of hydrogen and hydrogen-containing species. The integration of the measurement setup/reactor into the neutron beamline enables the temporally resolved measurement of the distribution of adsorbed water on the catalyst under operating conditions (<i>p</i>, <i>T</i>). The resulting quantitatively determined partial pressure of the water thus indirectly enables the spatial and temporal conversion of the processes. The knowledge gained from this experimental approach, combined with modelling, allows the design of reactor dimensions under optimized reaction conditions. The good agreement between simulation and experimental neutron imaging warrants the method as a reliable instrument for reactor characterization and design, with the prospect of its application on reactors on the industrial scale.