화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.35, No.13, 6747-6756, 2010
Reactivity of Ce-ZrO(2) (doped with La-, Gd-, Nb-, and Sm-) toward partial oxidation of liquefied petroleum gas: Its application for sequential partial oxidation/steam reforming
Ce-ZrO(2) was found to have useful partial oxidation activity under moderate temperatures. It converted liquefied petroleum gas (LPG) to H(2), CH(4), CO and CO(2) with small amounts of C(2)H(6) and C(2)H(4) formations depending on the operating temperature and provided significantly greater resistance toward carbon deposition compared to conventional Ni/Al(2)O(3). The doping of La, Sm and Gd over Ce-ZrO(2) considerably improved catalytic reactivity, whereas Nb-doping reduced its reactivity. It was found that the impact of doping element is strongly related to the degrees of oxygen storage capacity (OSC) and/or lattice oxygen (O(O)(x)) of materials. Among all catalysts, La-doped Ce-ZrO(2) was observed to have highest OSC value and was the most active catalyst. Above 850 degrees C with inlet LPG/O(2) molar ratio of 1.0/1.0, the main products from the reaction over La-doped Ce-ZrO(2) were H(2), CH(4), CO, and CO(2). Practical application was then proposed by applying La-doped Ce-ZrO(2) as primary oxidative catalyst for sequential partial oxidation/steam reforming of LPG (by using Ni/ Al(2)O(3) as the steam reforming catalyst). At 850 degrees C, this coupling pattern offered high H(2) yield (87.0-91.4%) without any hydrocarbons left in the products indicating the complete conversion of LPG to syngas. H(2) yield from this system was almost identical to that observed from the typical autothermal reforming over Rh/Al(2)O(3); hence it could efficiently replace the requirement of expensive noble metal catalysts to reform LPG properly. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.