Improved water dissociation and nitrous oxide decomposition by in situ oxygen removal in perovskite catalytic membrane reactor

The equilibrium controlled water dissociation and the kinetically controlled nitrous oxide (N2O) decomposition were studied in the perovskite BaCoxFeyZr1-x-yO3-delta (BCFZ) oxygen-permeable membrane reactor. By increasing the temperature or pressure difference and by feeding reducing gases like methane or ethane to the permeate side to consume the permeated oxygen, hydrogen production rate or N2O conversion could be enhanced. A hydrogen production rate of 3.1 cm(3) min(-1) cm(-2) was obtained at 950 degrees C. When methane was used as the reducing gas on the shell side, the oxygen concentration on the N2O side can be kept at a low level, thus avoiding the inhibition of the N2O decomposition by adsorbed surface oxygen species. A complete decomposition of N2O for gas streams containing 20 vol.% N2O was achieved on the core side at 850 degrees C. Simultaneously, methane on the shell side was converted into synthesis gas with CO yield of above 80%. When feeding ethane to the shell side, the hydrogen from the thermal dehydrogenation of ethane can consume the permeated oxygen. At 850 degrees C. an ethane conversion of 85% and an ethylene selectivity of 86% were obtained. (C) 2010 Elsevier B.V. All rights reserved.