Catalytic pre-mixed fibre burners

The performances of three pre-mixed fibre burners (maximum rated power: 30 kW), based on the same FeCrAlloy porous support, were tested in a specific pilot plant. The first one was a commercial FeCrAlloy panel (the reference burner); the other two were catalytically activated by deposition onto the fibres of the LaMnO(3) perovskite, according to two different procedures:'direct' and 'indirect route'. The latter, in which an LaAlO(3) layer was placed between the catalyst and the fibres to prevent deactivation, should be preferred for the presumably major stability and constant performance in the long term. The flue gas temperature, the NO(x), CO and HC flue gas concentrations and the emission intensity of the panel surface, were measured as a function of E(a) (excess of air) and Q (specific heat power). Besides, the operating combustion regimes (radiant, transition and blue-flame) were identified by direct observation of the burner surface. As compared to the non-catalytic burner, the two catalytic ones enabled, with nearly unchanged NO(x) production, up to about 5 times lower CO and HC emissions, particularly in the radiant combustion regime. As a result, a wider rangeability of the burner (down to about 10% of the maximum specific operating power, where non-catalytic burner failed), with environmentally acceptable flue gas composition, was achieved. (C) 1999 Elsevier Science Ltd. All rights reserved.