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Catalytic oxidation removal of gaseous elemental mercury in flue gas over niobium‐loaded catalyst
Author(s) -
Honghu Li,
Jiangjun Hu,
He Wang
Publication year - 2016
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.22516
Subject(s) - flue gas , catalysis , niobium , x ray photoelectron spectroscopy , inorganic chemistry , chemistry , catalytic oxidation , combustion , fourier transform infrared spectroscopy , chemical engineering , organic chemistry , engineering
Nb‐Co‐Ce/Al 2 O 3 catalysts prepared by impregnation, sol‐gel method, and co‐precipitation were examined for elemental mercury (Hg 0 ) oxidation in a simulated coal combustion flue gas. The catalysts were characterized by SEM‐EDS, BET, XRD, FTIR, and XPS techniques. The performances of different niobium‐loaded catalysts on Hg 0 oxidation efficiency with regard to preparation method, assistant, reaction temperature, and typical individual flue gas were investigated. The results showed that the Hg 0 oxidation efficiency performed at the highest value for niobium‐loaded catalysts at 523 K. SO 2 was observed to have a negative effect on Hg 0 oxidation. The niobium‐loaded catalysts prepared by the sol‐gel method and co‐precipitation exhibited higher Hg 0 oxidation efficiency than that prepared by impregnation, due to higher specific surface area and more exposure of active sites. However, it also results in these catalysts being affected by SO 2 more easily. An enhancing effect of O 2 was observed and an addition of HCl would promote the Hg 0 oxidation further. Results also indicated that synergistic effects between NbO x , CoO x , and CeO x could promote the sustainable capacity of Hg 0 oxidation for Nb‐Co‐Ce/Al 2 O 3 catalysts. Hg 0 oxidation over Nb‐Co‐Ce/Al 2 O 3 catalysts is thought to follow a Mars‐Maessen mechanism in which lattice oxygen derived from NbO x would react with absorbed Hg 0 .