Numerical analysis of a catalytic radiant burner: effect of catalyst on radiant efficiency and operability

In this paper we study a new class of porous direct-fired radiant burners w hich burn part of the fuel catalytically The burner consists of a multiple- layer porous medium, with one layer that is partially coated with an oxidiz ing catalyst. Simulations are performed to investigate the effect of platin um catalyst loading, location of catalyst layer, and its thickness on burne r performance for single layer and bilayer porous media. Significant effici ency gains are found, but only when the catalyst was placed on the downstre am edge of the porous medium. The porous medium was generally not hot enoug h to cause significant deterioration of the catalyst. Only a thin layer of catalyst is required for efficiency improvements. Enlarging the catalytic z one into cold temperature regions has almost no effect on burner performanc e. Heat release due to the catalyst occurs inside the porous medium, thus r esulting in a higher radiant efficiency. (C) 1999 Elsevier Science B.V. All rights reserved.