Fabrication of SiC and Al₂O₃ foams by replica method for premixed porous burner application

This article presents the preparation of two-layer ceramic foams with different pore sizes for porous media combustion (PMC) application and the analysis of combustion characteristics. The two-layer of ceramic foams are required for flame stabilization as stated by previous works which consists of the following: combustion layer with larger pore size and preheat/mixing layer with smaller pore size. Aluminum oxides (Al₂O₃) and silicon carbide (SiC) are the materials for preheat/mixing and combustion layers, respectively. Both Al₂O₃ and SiC foams were prepared by using the replica method, where the polyurethane sponge is soaked in each Al₂O₃ and SiC slurry. Sintering temperature at 1200°C was found adequate for the ceramic foams to be strong enough for handling and use in combustion. The two-layer ceramic foams were tested in PMC using premixed burner with liquified petroleum gas (LPG) as the fuel and air as an oxidizer. Temperature distribution as well as combustion gases product i.e. carbon monoxide (CO) and nitrogen oxides (NOx) were measured and analyzed. As for the combustion characteristics, the PMC has shown better temperature distribution compared to free flame combustion (FFC) while about 64% and 59% reduction for CO and NOx emissions, respectively.