Overcoming the engineering constraints for scaling-up the state-of-the-art catalyst for tail-gas N2O decomposition

An efficient process is reported for preparing a state-of-the-art Fe-ferrierite catalyst for N2O decomposition under industrial tail-gas conditions. In the synthesis procedure we evaluate the very demanding constraints for scale-up; i.e. large reactor volumes are typically needed, long processing times and considerable amounts of waste water is generated. The proposed synthesis minimizes the amount of water used, and therefore the amount produced waste water is minimal; in this approach there is no liquid residual water stream that would need intensive processing. This has remarkable benefits in terms of process design, since the volume of equipment is reduced and the energy-intensive filtration is eliminated. This route exemplifies the concept of process intensification, with the ambition to re-engineer an existing process to make the industrial catalyst manufacture more sustainable. The so-obtained catalyst is active, selective and very stable under tail gas conditions containing H2O, NO and O2, together with N2O; keeping a high conversion during 70 h time on stream at 700 K, with a decay of 0.01%/h, while the standard reference catalyst decays at 0.06%/h; hence it deactivates six times slower, with ~5% absolute points of higher conversion. The excellent catalytic performance is ascribed to the differential speciation.