Perovskite oxide absorbents for oxygen separation

✍ Scribed by Yufeng He; Xuefeng Zhu; Qiming Li; Weishen Yang

• Publisher: American Institute of Chemical Engineers
• Year: 2009
• Tongue: English
• Weight: 308 KB
• Volume: 55
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.11931

✦ Synopsis

Abstract

The fixed‐bed oxygen absorption processes of the series of Ba~1−x~Sr~x~Co~0.8~Fe~0.2~O~3−δ~ oxides were studied by oxygen partial pressure swing absorption in the temperature range of 300–850°C. The results show that SrCo~0.8~Fe~0.2~O~3−δ~, with the smallest A‐site ion radius, has the largest oxygen absorption capacity (0.402 mmol/g) at 500°C. The oxygen absorption and desorption kinetics fit well with the pseudo‐second‐order kinetics model. Comparing the modeling absorption rate coefficient k~2~ with the desorption rate coefficient k~2~′, all the oxides studied had higher oxygen absorption rates than oxygen desorption ones. In addition, the combined results of X‐ray diffraction analysis, O~2~‐TPD, room temperature iodometric titration, and thermogravimetric analysis explained the relationship between the oxygen absorption capacities and the average radii of the A‐site ions for this series of Ba~1−x~Sr~x~Co~0.8~Fe~0.2~O~3−δ~ in the temperature range of 300–600°C. © 2009 American Institute of Chemical Engineers AIChE J, 2009