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Influence of sodium on deactivation and regeneration of SCR catalyst during utilization of Zhundong coals
Author(s) -
Du Yongbo,
Wang Chang'an,
Lv Qiang,
Deng Lei,
Che Defu
Publication year - 2016
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.2031
Subject(s) - catalysis , chemistry , sodium , sodium hydroxide , alkali metal , selective catalytic reduction , coal , deposition (geology) , inorganic chemistry , chemical engineering , organic chemistry , paleontology , sediment , engineering , biology
Abstract Zhundong coals have a super huge reserve and many excellent characteristics. However, the sodium content in Zhundong coal is extremely high, which can accelerate the deactivation of the V‐W‐TiO 2 selective catalytic reduction (SCR) catalysts. In the present work, the solution impregnation method was adopted to investigate the effect of alkali metals deposition on the SCR catalysts, while various approaches were employed to regenerate the poisoned catalysts. Experimental results indicate that sodium deposition significantly deactivates the catalytic performance of SCR catalysts and sodium hydroxide (NaOH) presents the most serious deactivation. The catalytic ability of sodium poisoned catalyst is only slightly recovered by water washing, whereas it could be improved to approach that of the fresh catalyst by acid solution washing. The regeneration effect of sulfation with SO 2 is between those of water washing and acidic solution washing. Further characterizations validated that the deactivation is mainly caused by the damage of surface acid sites. Acidic solution can remove more than 75 wt% of the deposited sodium and provide new acid sites on catalyst surface. Therefore, acidic solution washing is a satisfactory method to regenerate poisoned SCR catalysts for power plants firing high‐sodium coals. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.