Thermodynamic and experimental studies of catalytic reforming of exhaust gas recirculation in gasoline engines

The catalyst 1 wt% Rh supported on ZrO2(73.8 wt%)-La2O3-Nd2O3-Y2O3(26.2 wt%) was tested for the reforming of exhaust gas recirculation (REGR) on gasoline engines. Isooctane (C8H18) was used as molecule representative of gasoline, and N-2, H2O, CO2 and O-2 were used as model exhaust gas. Despite the moderate C8H18 conversion (58-70%) and a slight initial deactivation, good stability and activity were obtained even after hydrothermal treatment of the catalyst, leading to a gas phase composition close to thermodynamic equilibrium. The volume proportion of H-2 produced in the gas phase achieved 14% which is consistent with the sake of the application. The high hydrogen yield was linked to the very low methane production. C8H18 steam reforming (SR) and C8H18 dry reforming (DR) reactions in REGR conditions were also studied. The presence of CO2 decreased the H-2 yield expected with respect to SR reaction. A suitable model based on experimental isooctane conversion and thermodynamic calculations predicted this result. (C) 2010 Elsevier B.V. All rights reserved.