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Transport effects and chemical effects on NO removal by SCR with NH 3 over iron‐based catalyst in a magnetically fluidized bed
Author(s) -
Yao Guihuan,
Gui Keting,
Ling Xiang
Publication year - 2018
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23207
Subject(s) - catalysis , chemisorption , chemistry , paramagnetism , magnetic field , chemical reaction , magnetization , magnet , condensed matter physics , physics , organic chemistry , quantum mechanics
Selective catalytic reduction (SCR) of NO by NH 3 on iron‐based catalysts was investigated with a magnetically fluidized bed (MFB). Magnetic fields promoted the NO conversion. The optimal efficiency of 95 % was attained under a magnetic field of 0.01–0.015 T at 250 °C. Magnetic fields yielded transport effects and chemical effects on SCR of NO over Fe 2 O 3 catalyst. The transport effects are reflected by the enhancement of physical transfer in a MFB. Magnetic fields can check and eliminate bubbles, increase gas‐solid contact probabilities, and thereby improve heat and mass transfer characteristics in a MFB. The chemical effects can be summarized into three points. First, the magnetization of γ ‐Fe 2 O 3 by uniform magnetic fields gives rise to boundary effects, which results in Faraday force on paramagnetic NO molecules and yields NO movement to the catalyst surface, and hence increases NO chemisorption. Second, the synergy of magnetic fields and ferrimagnetic iron‐based catalyst can boost the transformation of antimagnetic reactant into paramagnetic products, and accelerate electron transport in the reaction, which enhances the activation of NH 3 on magnetic Fe (III) sites. Third, magnetic fields can alter the energy dispersal of a free radicals reaction system, and thereby promotes the free radicals reaction between NH 2 · and NO·.