Effects of foam structure and material on the performance of premixed porous ceramic burner

Abstract

An experimental setup was developed to investigate the physical characteristics of ceramic foam, used in reaction layer, on the performance of a porous burner. This premixed burner included mainly four sections: premixed, preheating, combustion zone and an integrated heat exchanger. The objective of this work was to investigate effects of different kinds of ceramic foams with various porosity, pore density and materials on the burner performance. The combustor was operated with natural gas and diverse structures of alumina and silicon carbide foam utilized in the reaction layer. Temperature distribution along the centerline, thermal efficiency, emission concentration and pressure drop were thoroughly investigated. Results showed a decrease in the porosity of ceramic foams, causing emission and pressure drop to increase while efficiency declined. More stable combustion was achieved by using finer foams with higher pore density. These foams indicated lower pollution and higher efficiency in low excess air, while coarser foams—ceramic foams with low pore density—resulted in lower pollution and higher efficiency in high excess air. Investigation effect of material exhibited silicon carbide foams causing higher temperature of the combustion and more temperature variation through the burner. Generally, material effect was negligible in terms of efficiency. But role of material highlighted in pollution where silicon carbide resulted in higher amount of NO.