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Performance of Low‐temperature SCR of NO with NH 3 over MnO x /Ti‐based catalysts
Author(s) -
Niu Yanqing,
Zhang Xiaolu,
Zhang Hao,
Liang Yang,
Li Shuaifei,
Yao Qi,
Wang Denghui,
Hui Shi'en
Publication year - 2019
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.23400
Subject(s) - catalysis , space velocity , selectivity , selective catalytic reduction , crystallite , manganese , amorphous solid , x ray photoelectron spectroscopy , inorganic chemistry , materials science , anatase , nuclear chemistry , chemistry , chemical engineering , metallurgy , photocatalysis , organic chemistry , engineering
The effects of Mn loadings and precursors, catalyst preparation methods, incineration durations and temperatures, and the addition of Co and Ce on NO‐reduction efficiency and selectivity (N 2 O formation) during the preparation of MnO x /Ti‐based catalysts were studied by micropore‐size analysis (XRD, XPS, SEM, and FTIR), while considering changeable parameters. Meanwhile, the performance of low‐temperature SCR of NO with NH 3 over the designed catalysts was tested under various gas hourly space velocities (GHSVs), NH 3 /NO molar ratios, and contents of NO, NH 3 , O 2 , H 2 O, and SO 2 in a lab‐scale reactor. Overall, the Mn(0.3)Ce(0.1)/Ti catalyst, which had high NO‐reduction efficiency and selectivity (low N 2 O formation), was recommended, with the following preparation methods: ultrasonic impregnation; manganese acetate precursor; and incineration at 500 °C. Appropriate textural properties (high surface area and small pore and crystallite sizes), well‐dispersed amorphous manganese (rather than crystalline) on the anatase surface (rather than rutile), abundant active sites, and long residence time are essential for high NO‐reduction efficiency. In practice, NO‐reduction efficiency decreased with increasing GHSV and the NH 3 and NO contents; however, it initially increased and then became saturated with an increasing NH 3 /NO molar ratio and O 2 content. Water deactivated the catalyst to a recoverable state, whereas SO 2 resulted in unrecoverable deactivation.