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Aging of Premixed Metal Fiber Burners for Natural Gas Combustion Catalyzed with Pd/LaMnO 3 ·2ZrO 2

2007; American Chemical Society; Volume: 46; Issue: 21 Linguagem: Inglês

10.1021/ie061665y

1520-5045

Stefania Specchia, Marcela A. Ahumada Irribarra, Pietro Palmisano, Guido Saracco, Vito Specchia,

Thermochemical Biomass Conversion Processes

The aim of this work is the study of the aging effect induced by S-compounds added as odorants in the natural gas network over a previously developed catalysts now deposited on a FeCrAl alloy fiber mat (NIT 200/S by ACOTECH BV). A novel generation of catalytic premixed fiber burners for low-environmental-impact natural gas combustion are based on Pd/LaMnO3·2ZrO2 catalyst, where ZrO2 acts as a structural promoter and the noble metal/perovskite synergism is effectively exploited, leading to enhanced performances with respect to noncatalyzed burners. The catalytic premixed fiber burners were characterized by means of field emission scanning electron microscope/energy dispersive spectrometer (FESEM/EDS), temperature programmed desorption/reduction/oxidation (TPD/R/O), and thermogravimetric/mass spectroscopy (TG/MS) techniques. The combustion runs were accomplished in a domestic boiler pilot plant under realistic operating conditions. An unexpected improvement was found in the overall performance of catalyzed burners after sulfur aging carried out up to 3 weeks (the catalyzed burners were kept in an electric oven at 800 °C under a N2 flow containing 200 ppmv of SO2). Despite the effect of catalyst thermal stress and aging, the overall performance, in terms of pollutant emissions, was preserved after accelerated lifetime utilization. This is probably due to the presence of microfractures on the aged burners, accomplished by an increase of active sites for β-type oxygen desorption, able to improve methane combustion.