Development of highly effective supported nickel catalysts for pre-reforming of liquefied petroleum gas under low steam to carbon molar ratios

摘要

The pre-reforming of commercial liquefied petroleum gas (LPG) was investigated over Ni-CeO_2 catalysts at low steam to carbon (S/C) molar ratios less than 1.0. It was found that the catalytic activity and selectivity depended strongly on the nature of the support and the interaction between Ni and CeO_2. The Ni-CeO_2/Al_2O_3 catalysts, which were prepared by impregnating boehmite (AlOOH) with an aqueous solution of cerium and nickel nitrates, exhibited the optimal catalytic activity and remarkable stability for the steam reforming of LPG in the temperature range of 275-375 ℃. The effects of CeO_2 loading, reaction temperature and S/C ratio on the catalytic behavior of the Ni-CeO_2/Al_2O_3 catalysts were discussed in detail. The results showed that the catalysts with 10 wt.% CeO_2 had the highest catalytic activity, and higher S/C ratios contributed to LPG reforming and the methanation of carbon oxides and hydrogen. The XRD and H_2-TPR analyses revealed that the strong interaction between Ni and CeO_2 resulted in the formation of CeAlO_3 in the Ni-CeO_2/Al_2O_3 catalysts reduced. The stability tests of 15Ni-10CeO_2/Al_2O_3 catalyst at 350 ℃ indicated that the catalyst was stable, and the stability could be enhanced by increasing S/C ratio.