| Rhodium, platinum, copper, palladium, and rhodium-ceria catalysts were investigated in the catalytic partial oxidation of methyl acetate, the simplest methyl ester, to better understand the conversion of biodiesel to hydrogen. Only rhodium and rhodium-ceria catalysts allowed for an autothermal reactor operation. Both catalysts were active in producing hydrogen, carbon monoxide, water, and carbon dioxide, although the rhodium-ceria catalyst showed the greater methyl acetate conversion and the greater hydrogen and carbon monoxide selectivities. A low C/O feed ratio favored the methyl acetate conversion, the hydrogen selectivity, and the carbon monoxide selectivity. Furthermore, a high gas hourly space velocity also improved the reactor performance. According to the experimental data, it appears that the oxidation of methyl acetate forms carbon monoxide and water as a primary step, instead of carbon dioxide and water as with the combustion reaction. In general, methyl acetate does not yield more synthesis gas than biodiesel. The methyl ester functional group limits the hydrogen yield and hence new catalysts should be developed and investigated in order to better target the decomposition of methyl esters to hydrogen. |
