Novel Cobalt-Free, Noble Metal-Free Oxygen-Permeable 40Pr_0.6Sr_0.4FeO_3-δ–60Ce_0.9Pr_0.1O_2−δ Dual-Phase Membrane

Abstract

A novel cobalt-free and noble metal-free dual-phase oxygen-transporting membrane with a composition of 40 wt % Pr0.6Sr0.4FeO3−δ–60 wt % Ce0.9Pr0.1O2−δ (40PSFO–60CPO) has been successfully developed via an in situ one-pot one-step glycine-nitrate combustion process. In situ XRD demonstrated that the 40PSFO–60CPO dual-phase membrane shows a good phase stability not only in air but also in 50 vol % CO2/50 vol % N2 atmosphere. When using pure He or pure CO2 as sweep gases, at 950 °C steady oxygen permeation fluxes of 0.26 cm3 min–1 cm–2 and 0.18 cm3 min–1 cm–2 are obtained through the 40PSFO–60CPO dual-phase membrane. The partial oxidation of methane (POM) to syngas was also successfully investigated in the 40PSFO–60CPO dual-phase membrane reactor. Methane conversion was found to be higher than 99.0% with 97.0% CO selectivity and 4.4 cm3 min–1 cm–2 oxygen permeation flux in steady state at 950 °C. Our dual-phase membrane - without any noble metals such as Ag, Pd or easily reducible metals oxides of Co or Ni - exhibits high oxygen permeation fluxes as well as good phase stability at high temperatures. Furthermore, the dual-phase membrane shows a good chemical stability under the harsh conditions of the POM reaction and in a CO2 atmosphere at high temperatures.

A novel CO2-stable dual phase membrane with high oxygen permeability

“…However, the PSF phase without Co in the dual phase CP-PSF powder retains the orthorhombic symmetry under the same conditions. 16 The phase transition from rhombohedral to cubic symmetry at high temperatures is in agreement with the findings for the comparable materials La 0.6 Sr 0. 19 The formation of the cubic structure of the PSFC phase at high temperatures is beneficial for oxygen permeability.…”

“…However, the low oxygen permeability of dual phase membranes needs to be improved to meet the industrial application requirements. 11 Zhu et 16 The CP-PSF membrane shows a good chemical stability under the harsh conditions of the POM reaction and in a CO 2 atmosphere at high temperatures. 16 Thus, cobalt-doping of the PSF phase in the dual phase CP-PSF membrane can enhance the oxygen vacancy concentration in the membrane lattice, which should result in a combination of good CO 2 stability and high oxygen permeability.…”

“…11 Zhu et 16 The CP-PSF membrane shows a good chemical stability under the harsh conditions of the POM reaction and in a CO 2 atmosphere at high temperatures. 16 Thus, cobalt-doping of the PSF phase in the dual phase CP-PSF membrane can enhance the oxygen vacancy concentration in the membrane lattice, which should result in a combination of good CO 2 stability and high oxygen permeability. In this paper, we present the novel dual phase membrane, 60 wt% Ce 0.9 Pr 0.1 O 2Àd -40 wt% Pr 0.6 Sr 0.4 Fe 0.5 Co 0.5 O 3Àd (abbreviated as CP-PSFC) prepared via a one-pot sol-gel synthesis method.…”

A CO2-stable reduction-tolerant Nd-containing dual phase membrane for oxyfuel CO2capture

“…Combining the in situ XRD, the reversibility of the oxygen permeation measurements when switching the sweep gases from CO 2 to He, and the stable oxygen permeation uxes on our 40NSFO-60CNO, we can exclude chemical reactions between the two NSFO and CNO phases involved such as those reported in previous studies of dual phase membranes. 7,8,20,21 40NSFO-60CNO membrane reactor in the partial oxidation of methane (POM) to synthesis gas Fig. 7 presents the temperature inuence on CH 4 conversion, CO selectivity and oxygen permeation ux through the 40NSFO-60CNO dual phase membrane in the POM to synthesis gas.…”

“…[3][4][5][6] A challenging application of OTMs would be the oxyfuel process with integrated CO 2 capture. 7,8 However, to survive under real process conditions in the presence of harsh gases (such as CO 2 , H 2 , CH 4 , etc.) at high temperatures, a dense oxygen separation membrane should possess the following properties: (i) high oxygen permeation uxes; (ii) good structural stability within appropriate ranges of temperature and oxygen partial pressure; (iii) sufficient chemical compatibility and mechanical strength.…”