Oxidative Steam Reforming and Steam Reforming of Methane, Isooctane, and N-Tetradecane over an Alumina Supported Spinel-Derived Nickel Catalyst

摘要

The present work is focused on analyzing the potential of an alumina-supported spinel-derived nickel catalyst for oxidative steam reforming and steam reforming of model hydrocarbons present in gasoline and diesel, namely, isooctane and n-tetradecane, respectively. For comparative purposes these reforming processes have also been investigated for methane, and the catalytic behavior of a commercial rhodium catalyst has been evaluated as well. When operating with a relatively high volume hourly space velocity (equivalent to 60 000 cm(3) C g(-1) h(-1)) at a low temperature (600 degrees C) for 31 h time on stream, the activity of the investigated nickel catalyst is high and, more importantly, stable in the reforming of methane (by either steam reforming or oxidative steam reforming) and the oxidative steam reforming of isooctane. As for n-tetradecane a significant loss of activity with time on line is found, more pronounced under steam reforming conditions. Although the presence of oxygen helps in controlling coking, the reforming of this heavy feed unavoidably results in a substantial formation of graphitic filaments with a high chemical stability. Additionally, sintering and partial oxidation of the metallic phase have been also observed, mainly under oxidative steam reforming conditions. Finally, it can be concluded that when compared with a commercial rhodium catalyst, the prepared nickel catalyst derived from NiAl2O4 is a more efficient reforming catalyst for fuels with varying chemical nature.