Rapid glycine-nitrate combustion synthesis of the CO2-stable dual phase membrane 40Mn1.5Co1.5O4−δ–60Ce0.9Pr0.1O2−δ for CO2 capture via an oxy-fuel process

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 40wt% Mn1.5Co1.5O4−δ–60wt% Ce0.9Pr0.1O2−δ (40MCO–60CPO). After sintering at 1300°C in air for 10h, 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 0.48mLcm−2min−1 was obtained for a 0.3mm 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 60h 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.