Removal of NO by methane over iron in simulated flue gas with SO2. (15th April 2016)

• Record Type: Journal Article
• Authors: Su, Yaxin; Zhao, Bingtao; Deng, Wenyi
• Is Part Of: Fuel. Volume 170(2016)
• Page Start: 9
• Page End: 15
• Publication Date: 2016-04-15
• Subjects: NO reduction -- Methane -- Iron -- Iron oxides -- SO2; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2015.12.021
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Effect of SO2 on NO reduction by CH4 over iron was investigated. Metallic iron could simultaneously reduce almost 100% of NO and SO2 above 700 °C. SO2 had little influence on NO reduction. NO reduction was higher than 95% above 850 °C. Abstract: The effect of SO2 on NO reduction by methane over iron and/or iron oxides was experimentally investigated at 300–1000 °C in a tubular flow reactor. NO reduction efficiencies vs temperature were presented at typical conditions and the reaction product scales were analyzed by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) methods. In N2 atmosphere with 0.01–0.04% SO2, iron simultaneously reduced 100% of NO and SO2 above 700 °C. In simulated flue gas atmosphere with 0.01–0.04% SO2, NO reduction efficiency was higher than 95% and 98% when the temperature was above 850 °C and 950 °C respectively at fuel rich conditions. The influence of SO2 on NO reduction was insignificant. In a continuous test in simulated flue gas containing 0.02% SO2, 0.05% NO, 16.8% CO2, 2.0% O2, experimental data demonstrated that more than 95% of NO was reduced by 1.13% methane over iron at 1000 °C over 100 h. The mechanism for the reaction of SO2 with Fe and CH4 was discussed. When iron was exposed to the flue gas mixtures of NO/SO2 /CH4, iron reacted with both NO and SO2 and the reaction product was a mixture of Fe2 O3 /Fe3 O4 /FeO and FeS. CH4 reduced the iron oxides to iron, at the same time CH4 reacted with SO2 to produce elemental sulfur and H2 S. Then H2 S reacted with iron/iron oxides to form FeS.