• Title, Summary, Keyword: $La_{0.7}Sr_{0.3}Co_{0.2}Fe_{0.8}O_{3-{\delta}$ membrane

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Preparation and Oxygen Permeability of Tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ Membranes with $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$ Porous Coating Layer (다공성의 $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$가 코팅된 $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막의 제조 및 투과 특성)

  • Kim, Jong-Pyo;Pyo, Dae-Woong;Park, Jung-Hoon;Lee, Yong-Taek
    • Membrane Journal
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    • v.22 no.1
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    • pp.8-15
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    • 2012
  • Tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ membranes with $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$ porous coating layer were prepared by extrusion and dip coating technique. XRD and SEM result showed the tubular membrane possessed the perovskite structure and porouscoating layer (thickness= about $2{\mu}m$) in surface. The oxygen permeation test was measured at condition of ambient air (feed side) and vacuum (permeate side) in the temperature range from 750 to $950^{\circ}C$. The oxygen permeation flux of $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ tubular membrane with $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$ porous coating layer reached maximum $3.2mL/min{\cdot}cm^2$ at $950^{\circ}C$ and was higher than non-coated $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ tubular membrane. Long-term stability test result indicated that the oxygen permeation flux was quite stable during the 11 day.

Preparation and Oxygen Permeation Properties of La0.07Sr0.3Co0.2Fe0.8O3-δ Membrane (La0.07Sr0.3Co0.2Fe0.8O3-δ 분리막의 제조 및 산소투과 특성)

  • Park, Jung Hoon;Kim, Jong Pyo;Baek, Il Hyun
    • Applied Chemistry for Engineering
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    • v.19 no.5
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    • pp.477-483
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    • 2008
  • $La_{0.7}Sr_{0.3}Co_{0.2}Fe_{0.8}O_{3-{\delta}$ oxide was synthesized by a citrate method and a typical dense membrane of perovskite oxide has been prepared using as-prepared powder by pressing and sintering at $1300^{\circ}C$. Precursor of $La_{0.7}Sr_{0.3}Co_{0.2}Fe_{0.8}O_{3-{\delta}$ prepared by citrate method was investigated by TGA and XRD. Metal-citrate complex in precursor was decomposed into perovskite oxide in the temperature range of $260{\sim}410^{\circ}C$ but XRD results showed $SrCO_3$ existed as impurity at less than $900^{\circ}C$. Electrical conductivity of membrane increased with increasing temperature but then decreased over $700^{\circ}C$ in air atmosphere ($Po_2=0.2atm$) and $600^{\circ}C$ in He atmosphere ($Po_2=0.01atm$) respectively due to oxygen loss from the crystal lattice. The oxygen permeation flux increased with increasing temperature and maximum oxygen permeation flux of $La_{0.7}Sr_{0.3}Co_{0.2}Fe_{0.8}O_{3-{\delta}$ membrane with 1.6 mm thickness was about $0.31cm^3/cm^2{\cdot}min$ at $950^{\circ}C$. The activation energy for oxygen permeation was 88.4 kJ/mol in the temperature range of $750{\sim}950^{\circ}C$. Perovskite structure of membrane was not changed after permeation test of 40 h and the membrane was stable without secondary phase change with 0.3 mol Sr addition.

Further improvements in oxygen permeation properties of La0.6Sr0.4Ti0.3Fe0.7O3-δ coated Ba0.5Sr0.5Co0.8Fe0.2O3-δ hollow fiber membrane

  • Park, Se Hyung;Magnone, Edoardo;Park, Jung Hoon
    • Journal of Industrial and Engineering Chemistry
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    • v.56
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    • pp.350-354
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    • 2017
  • Oxygen-permeable $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) hollow fiber membranes was prepared by a phase inversion spinning process. In the second stage, $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$ (LSTF) was coated on the surface of the prepared BSCF hollow fiber membranes by dip coating method in an attempt to improve not only the oxygen permeation performance but also the long-term chemical stability. The oxygen permeation fluxes were measured in the temperature range of $850-1000^{\circ}C$ in air. The oxygen permeation flux reached to $9.18mL/min/cm^2$ at $1000^{\circ}C$. In addition, long-term operation test results indicated that the oxygen permeation fluxes remained consistently during the 240 h operation. With the dual aims of reviewing existing work in the topic and understanding the effects of membrane morphology and thickness on the performance of BSCF membrane, the oxygen permeation property of LSTF-coated BSCF hollow fiber membrane with engineered morphology was compared directly with its corresponding uncoated case and then with other configuration types, such as BSCF disk-shaped and tubular BSCF membranes.

Temperature Dependence of Cr Impurity in La0.6Sr0.4Ti0.3Fe0.7O3-δ Coated Ba0.5Sr0.5Co0.8Fe0.2O3-δ Ion Conducting Membrane for oxygen Separation (산소 분리를 위한 La0.6Sr0.4Ti0.3Fe0.7O3-δ가 코팅된 Ba0.5Sr0.5Co0.8Fe0.2O3-δ 이온전도성 분리막에서 Cr 불순물의 온도 의존성)

  • Park, Yu Gang;Park, Jung Hoon
    • Korean Chemical Engineering Research
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    • v.57 no.1
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    • pp.11-16
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    • 2019
  • $La_{0.6}Sr_{0.4}Ti_{0.3}Fe_{0.7}O_{3-{\delta}}$(LSTF) coated $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$(BSCF) membranes which has properties of high oxygen permeability and stability to $CO_2$ were applied to a bench scale apparatus to conduct oxygen permeation experiments. Also, the membranes of the laboratory and the bench scale device were divided into three regions according to the temperature gradient in the membrane reactor for comparative analysis. While oxygen permeation experiment were conducted up to $900^{\circ}C$, temperature dependence of Cr deposition was investigated. As a result, it was confirmed that the oxygen permeability was $2.37ml/min{\cdot}cm^2$, which was significantly lower than $3.79ml/min{\cdot}cm^2$ measured in the laboratory apparatus. It was found through XRD and SEM/EDS analysis that the decrease in oxygen permeability was originated from the deposition of gaseous Cr on the membrane surface released from the alloy material of the housing. In particular, a large amount of Cr was found in the medium temperature region.

Fabrication and Characterization of $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta}$ Oxygen Permeation Membranes Prepared with Different Powders ($La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta}$ 산소 투과 분리막의 제조 및 특성)

  • Lim, Kyoung-Tae;Lee, Kee-Sung;Han, In-Sub;Seo, Doo-Won;Hong, Kee-Seog;Bai, Kang;Woo, Sang-Kuk;Cho, Tong-Lae
    • Journal of the Korean Ceramic Society
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    • v.38 no.10
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    • pp.886-893
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    • 2001
  • We synthesized $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta}$ powders by coprecipitation, citration and solid-state reactions. The oxygen permeation membranes were fabricated by cold isostatic pressing of the synthesized powders, followed by sintering in air. All powders and membranes consist of perovskite phases. The coprecipitated powders showed the highest surface area ($7.5m^2/g$) but strontium deficiency was found during washing and filtering in the process. The membrane with lower relative density was fabricated by citration method. On the other hand, solid state reacted powders had high relative density (95%), and mechanical properties showed superior properties. Especially, the composition of the solid-state reacted powders was relatively well-controlled.

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Fabrication and Oxygen Permeation Properties of ${La_{1-x}Sr_{x}B_{1-{\gamma}}Fe_{\gamma}O_{3-{\delta}}$(B=Co, Ga) Perovskite-Type Ceramic Membranes (${La_{1-x}Sr_{x}B_{1-{\gamma}}Fe_{\gamma}O_{3-{\delta}}$(B=Co, Ga) 페롭스카이트 세라믹 분리막의 제조 및 산소투과특성)

  • 임경태;조통래;이기성;한인섭;서두원
    • Membrane Journal
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    • v.11 no.4
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    • pp.143-151
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    • 2001
  • We have fabricated mixed-ionic conducting membranes, L $a_{0.6}$S $r_{0.4}$ $Co_{0.2}$F $e_{0.8}$ $O_{3-}$$\delta$/ and L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ by the solid state method. Ceramic membranes consisted of perovskite-type structures and exhibited high relative density, >95%. Especially, dense L $a_{0.6}$S $r_{0.4}$Co $O_{3-}$$\delta$/ layer was coated on the L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membranes by using screen printing technique in order to improve oxygen ion flux. We measured oxygen ion flux on uncoated L $a_{0.6}$S $r_{0.4}$ $Co_{0.2}$F $e_{0.8}$ $O_{3-}$$\delta$/, uncoated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/, and coated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membranes. The L $a_{0.6}$S $r_{0.4}$ $Co_{0.2}$F $e_{0.8}$ $O_{3-}$$\delta$/ membranes showed the highest flux, 0.26 mL/min.$\textrm{cm}^2$ at 90$0^{\circ}C$, after steady state had been reached. The oxygen flux of coated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membranes showed higher value, 0.19 mL/min.$\textrm{cm}^2$ at 95$0^{\circ}C$. This flux was as much as 2 or 3 times higher than those of uncoated L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membranes. 3-$\delta$/ membranes.X> 3-$\delta$/ membranes.membranes.

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