The strict control of nitrogen oxides(NOx)is an urgent task for improving China's air quali-ty,and selective catalytic reduction(SCR)with ammonia represents the dominant method for treatment of NOx exhaust from industries.As the focus of SCR denitrification shifts from thermal power plants to non-electric industries such as steel and cement kilns,the overall working temperature of SCR shows an obvious shift to lower temperatures.Specifically,the flue gas temperature for denitrification is usually below 150 ℃ when a desulfurization treatment is pre-installed.Under these circumstances,achieving long-term and stable operation of denitrification catalysts becomes a pivotal challenge for the application of SCR technology.A decrease in reaction temperature can exacerbate not only water and sulfur poisoning but also induce new deactivation problems due to ammonium nitrate deposition.There-fore,this comprehensive review presents the research progress on the poisoning resistance of SCR cata-lysts under ultra-low temperatures.The paper starts with introducing the changes in denitrification per-formance caused by temperature reduction.After briefly describing catalyst deactivation and its charac-teristics,the main focus is on the developed poisoning resistance strategies against water/sulfur/ammo-nium nitrate.These strategies are discussed from the perspectives of denitrification catalyst structure modulation,combined purification process selection,and regulation of the reaction atmosphere.Fur-thermore,we introduce the research progress on anti-poisoning strategies and provide a discussion of anti-poisoning mechanism.Finally,considering the practical application requirements,a prospect for the future development direction of poisoning resistance studies in ultra-low temperature denitrification is presented.
关键词
选择性催化还原/超低温脱硝/脱硝催化剂/抗中毒/硝铵
Key words
SCR/Ultra-low temperature denitrification/Denitrification catalysts/Poisoning resis-tance/Ammonium nitrate
维普
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