Effect of CO/CH₄ on Redox of Iron during NO Reduction by XRD/SEM

Abstract:

NO reduction by iron was conducted in a one-dimensional ceramic tubular reactor at 300 - 1100 °C with simulated flue gas of 0.05% NO in N₂ base. The evolution of metallic iron was investigated by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) methods. The effect of reducing gases including CO and CH₄ was analyzed on the redox of iron. Results showed that metallic iron was oxidized to its oxides after the reaction with NO. In N₂ atmosphere, Fe₃O₄ was the major iron oxide at 550 °C and Fe₂O₃ was the major iron oxide at 1100 °C. SEM image of the iron sample surface showed that the iron surface was smooth and dense after the iron reduced NO at 550 °C, however, the iron surface became porous after the iron reduced NO at 1100 °C. Reducing gas CO could reduce iron oxides to metallic iron. XRD result showed that a little FeO was found but metallic iron was still the dominant component of the iron sample after the reaction with NO in CO atmosphere. CO was not effective to maintain a durable NO reduction efficiency in simulated flue gas atmosphere while CH₄ was very effective. XRD result of the iron sample after the 100 hours durable test at 1050°C when 1.17% CH₄ was added into the simulated flue gas showed that the iron was not fully oxidized during the durable reaction.

• Periodical: Applied Mechanics and Materials (Volumes 448-453)
• Pages: 559-563
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.448-453.559
• Online since: October 2013
• Authors: Ya Xin Su*, Li Ming Ren, Wen Yi Deng
• Keywords: CH₄, Co, Iron, Iron Oxides, NO Reduction

References

[1] V I Parvulescu, P Grange and B Delmon: Catal. Today Vol. 46(1998), p.233.

[2] N Apostolescu, B Geiger, K Hizbullah, et al: Appl. Catal. B: Environ. Vol. 62(2006), p.104.

[3] W Weisweiler, E Mallonn, O Gorke: Chemie Ingenieur Technik, Vol. (75), p.72.

[4] J P Chen, M C Hausladen, R T Yang: J. Catal. Vol. 151(1995), p.135.

[5] C Belver, M A Vicente, A Martínez-Arias, et al: Appl. Catal. B: Environ. Vol. 50(2004), p.227.

[6] M Schwidder, M S Kumar, K Klementiev, et al: J. Catal. Vol. 231(2005), p.314.

[7] R Q Long, R T Yang: J. Catal. Vol. 194(2000), p.80.

[8] V V Lissianski, V M Zamansky, P M Maly: Combust. Flame Vol. 125(2001), p.1118.

[9] A N Hayhurst, A D Lawrence:, Combust Flame Vol. 110(1997), p.351.

[10] B Gradon, J Lasek: Fuel Vol. 89(2010), p.3505.

[11] A Su, Y Su, H Cheng:. Adv. Mater. Res. Vol. 616-618(2013), p.1849.

[12] N Birks and G H Meier: Introduction to high temperature oxidation of meta( Edward Arnold, London, 1983).