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Free keywords:
COMPOSITE MEMBRANES; PROCESS INTENSIFICATION; MANGANESE OXIDE; PERMEATION; PERMEABILITY; PEROVSKITE; MICROSTRUCTURE; SEPARATION; STABILITY; CONDUCTOR
Abstract:
A rapid one-pot combustion synthesis method based on glycine–nitrate, has been applied to prepare a novel oxygen transporting dual phase CO2-stable membrane of the composition 40 wt% Mn1.5Co1.5O4−δ–60 wt% Ce0.9Pr0.1O2−δ (40MCO–60CPO). After sintering at 1300 °C in air for 10 h, the 40MCO–60CPO membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), back scattered SEM (BSEM), and energy dispersive X-ray spectroscopy (EDXS), showing that the 40MCO–60CPO composite represents a micro-scale mixture of mainly the two phases MCO and CPO, but small amounts of MnO2 and (MnCo)(MnCo)2O4−δ were detected in the sintered membranes as well. The oxygen permeation fluxes through the 40MCO–60CPO dual phase membrane were measured at elevated temperatures (900–1000 °C) with one side of the membrane exposed to synthetic air and the other side to a CO2/He sweep gas stream. A stable oxygen permeation flux of 0.48 mL cm−2 min−1 was obtained for a 0.3 mm thick membrane under an air/CO2 oxygen partial pressure gradient at 1000 °C. It was also found that 40MCO–60CPO dual phase membranes are stable for more than 60 h even when pure CO2 was used as the sweep gas, which recommends 40MCO–60CPO membranes as promising candidates for 4-end membrane operation in an oxy-fuel power plant.
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