Abatement of SO2-NOx binary gas mixtures using a ferruginous active absorbent: Part I. Synergistic effects and mechanism

Yinghui Han , Xiaolei Li , Maohong Fan , Armistead G. Russell , Yi Zhao , Chunmei Cao , Ning Zhang , Genshan Jiang


Received May 20, 2014,Revised September 29, 2014, Accepted , Available online April 23, 2015

Volume 27,2015,Pages 55-64

A novel ferruginous active absorbent, prepared by fly ash,industrial lime and the additive Fe (VI), was introduced for synchronous abatement of binary mixtures of SO2-NOx from simulated coal-fired flue gas. The synergistic action of various factors on the absorption of SO2 and NOx was investigated. The results show that a strong synergistic effect exists between Fe(VI) dose and reaction temperature for the desulfurization. It was observed that in the denitration process, the synergy of Fe(VI) dose and Ca/(S+N) had the most significant impact on the removal of NO, followed by the synergy of Fe(VI) and reaction temperature, and then the synergy of reaction temperature and flue gas humidity. A scanning electron microscope(SEM) and an accessory X-ray energy spectrometer (EDS) were used to observe the surface characteristics of the raw and spent absorbent as well as fly ash. A reaction mechanism was proposed based on chemical analysis of sulfur and nitrogen species concentrations in the spent absorbent. The Gibbs free energy, equilibrium constants and partial pressures of the SO2-NOx binary system were determined by thermodynamics.

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