Natural gas combustion catalysts for environmental-friendly domestic burners

The present work deals with the analysis of low-environmental-impact premixed metal fibre burners (Fe–Cr–Al fibre mats) for natural gas combustion, characterized by a satisfactorily combustion performance. In particular, perovskite- and mixed oxides-based catalysts, in synergism with Pd, were suitably developed at powder level and subsequently deposited over metal fibre mattress. New catalytic burners based on LaMnO3-ZrO2, CeO2-ZrO2, BaCeO3-ZrO2 and Pd/LaMnO3-ZrO2, Pd/CeO2-ZrO2, Pd/BaCeO3-ZrO2 catalysts were studied determining, first of all, the optimal operating conditions for catalysts preparation via the solution combustion synthesis (SCS). After preliminary investigations at powder level, the catalysts were then deposited over metal fibre mats to obtain premixed burners for household appliances. The resulting structured catalysts were then tested on a commercial domestic boiler under realistic operating conditions. The obtained results with the Pd-based catalytic burners showed better performances compared with those of the commercial burner, in terms of CO emissions. The NO emissions, however, resulted somehow increased, especially at the low thermal power rates and air excess, whereas they slightly decreased at high air excess. The most interesting results in terms of CO emission reduction were obtained with the Pd/CeO2-ZrO2 catalyzed burner.