OXIDATIVE CONVERSION OF METHANE TO SYNGAS OVER LANIO3 PEROVSKITE WITH OR WITHOUT SIMULTANEOUS STEAM AND CO2 REFORMING REACTIONS - INFLUENCE OF PARTIAL SUBSTITUTION OF LA AND NI

摘要

Selective partial oxidation of methane to syngas over LaNiO3, La0.8Ca(or Sr)(0.2)NiO3 and LaNi1-xCoxO3 (where x = 0.2-1) perovskites at extremely short contact time ( approximate to 0.8 ms) has been investigated. Also, simultaneous oxidative conversion and steam and CO2 reforming of methane to syngas over LaNiO3 at short contact time ( approximate to 9 ms) has been studied at different temperatures and CH4/O-2 feed ratios. The catalysts, before and after reaction, were characterized by XRD and SEM. LaNiO3 perovskite shows high activity and selectivity in the oxidative conversion of methane to syngas. However, the partial substitution of its La by Ca or Sr and also the partial or complete substitution of its Ni by Co causes a large decrease in both its activity and its selectivity. LaNiO3 is transformed to its catalytically active form, Ni-0/La2O3, during the initial period of the process. This catalyst shows very good performance in the simultaneous oxidative conversion (which is exothermic) and steam and CO2 reforming reactions (which are endothermic) of methane to syngas, at short contact time, operating in a most energy efficient manner and also requiring only a little or no external energy. (C) 1996 Academic Press, Inc. [References: 35]