Oxygen separating membrane manufactured from Ba0.5Sr0.5Co0.8Fe0.2O3−δ perovskite-like material

Abstract

The dense thin membrane for oxygen separation was manufactured from Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ (BSCF) mixed oxide with perovskite-like structure prepared by the solid-state method. Properties of both powder and granulate (chemical and phase compositions, the specific surface area and the porosity) as well as sintered material (the apparent density, the apparent porosity, the water absorbability, the chemical composition, the crystallographic structure and microstructure), that affect the process of ion oxygen permeation through membrane, were determined. Parameters influencing on usable properties of membranes viz., the bending strength and the coefficient of thermal expansion were assessed as well. Effect of the sintering temperature on membrane structure was evaluated. The elaborated fabrication procedure enables one to manufacture membrane, in which microstructure is characterized by the presence of big grains as well as decreased concentration of grain boundaries. Measurements of the oxygen permeation through BSCF membrane revealed that the highest oxygen flux reaching 2.6 cm 3 O 2 / (cm 2 min) was obtained at 950 • C under air and helium flows equal to 1 dm 3 min −1 .

Chemically and thermo-mechanically stable LSM–YSZ segmented oxygen permeable ceramic membrane

“…In contrast, the BSCF exhibited a high initial oxygen permeability (approximately 3 ml/cm 2 min), but further testing was impossible due to the failure of the membrane during thermal cycles as a result of the high TEC of the BSCF. The flexural strengths of BSCF ( $ 50 MPa [41]), LSM ( $ 60 MPa [42]) are similar at the room temperature. It is also reported that the flexural strength of LSM/YSZ composite is about 150 MPa [14].…”

Processing and characterization of screen printing Ba0.5Sr0.5Co0.8Fe0.2O3−δ inks

“…Particle size distribution of the synthesized BSCF powder ranges from submicron size to 10 μm with a mean particle size of 3.2 μm as shown by the analysis of SEM images on the powders (figure 3) and, according to, the specific surface area is small (1.1 m 2 g −1 ). Moreover, the measurements of low-temperature nitrogen sorption showed that the BSCF powder exhibited only trace porosity (0.001 cm 3 g −1 [14]), which is an insignificant value of pores volumes per unit mass of sample. X-ray diffraction (XRD) pattern on the synthesized powders shows that cubic perovskite phase of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ is formed (figure 4).…”

“…The BSCF perovskite powder was manufactured from the appropriate metal oxides: Co 2 O 3 (minimal content of Co 70%, Sigma) and Fe 2 O 3 (99% of purity, Sigma-Aldrich), and metal carbonates: BaCO 3 (99.5% of purity, Chempur) and SrCO 3 (99% of purity, Chempur). The raw materials were mixed with ethyl alcohol and milled for 2 h. The obtained powder was calcined in the electrical furnace for 5 h at 950 • C. The process of milling and calcination was repeated three times to obtain monophasic material [14]. SEM images of the powder were collected with a FEI Quanta 200 ESEM TM in low vacuum mode, while the XRD pattern was obtained with a Bruker D8 Advance in the range 10 • ≤ 2θ ≤ 80 • .…”

Influence of (CoO, CaO, B 2 O 3 ) additives on thermal and dielectric properties of BaO–Al 2 O 3 –SiO 2 glass–ceramic sealant for OTM applications

“…Gromada et al [20] reported that best solution for use of BSCF membrane as oxygen transport membrane is in the shape of a tube. Materials sealing is difficult due to the high pressure differential although the sealing area per unit area of membrane surface is small in a tubular design.…”

“…It has been noted that the studies on hightemperature seals for mixed conducting membrane is rarely reported in literature. Gromada et al [19] reported that best solution for use of BSCF membrane as oxygen transport membrane is in the shape of tube. Sealing of the materials is difficult because of the high pressure differential although the sealing area per unit area of membrane surface is small in a tubular design.…”