Catalytic steam and autothermal reforming of used lubricating oil (ULO) over Rh- and Ni-based catalysts

Abstract

The steam reforming of used lubricating oil (ULO) over Ni- and Rh-based catalysts supported by Ce-ZrO 2 and Al 2O 3 is studied in the present work. Among all catalysts, Rh/Ce-ZrO 2 (5 wt % Rh) provides relatively higher reforming reactivity (in terms of ULO conversion and H 2 yield) with excellent resistance toward carbon deposition compared to the other three catalysts. At 850 °C after exposure in the steam reforming condition for 72 h, H 2 yield of 78.1% can be achieved from the reaction over Rh/Ce-ZrO 2. For Ni/Ce-ZrO 2 and Ni/Al 2O 3, significant deactivations with time are detected and H 2 yields of 55.3-58.7% are achieved after exposure for 72 h; in addition, considerable amounts of C 2H 4, C 2H 6 and C 3H 6 are also found in the product along with H 2, CO, CO 2, and CH 4. The effect of O 2 addition was further studied over Ni/Ce-ZrO 2 and Ni/Al 2O 3. It was found that this addition significantly reduces the degree of carbon deposition as well as promoting the conversion of hydrocarbons to CO and H 2. At a suitable amount of O 2, a high H 2 yield comparable to that of steam reforming over Rh-based catalysts can be achieved. Nevertheless, it must be noted that introducing too high an O 2 content resulted in lower H 2 production due to the combustion of H 2 and ULO by O 2 addition. © 2010 American Chemical Society.