Abstract: Nitrogen oxides (NOx) emission of sintering flue gas accounts for more than half of the total NOx emission in the steel industry. With the increasingly stringent environmental regulations, the existed and new sintering machines equipped only with the denitration equipment of flue gas can meet the requirements of NOx emission regulations. Activated carbon has an abundant microporous structure, large specific surface area, and strong absorption capacity. SO2, NOx, dust, and other harmful gases of flue gas can be removed simultaneously by activated carbon at low temperature. Therefore, denitration of sintering flue gas on activated carbon has significant technical characteristics and advantages at low temperatures. However, the poor sulfur and water resistance of activated carbon limits its wide utilization in the denitration of low-temperature flue gas. The denitration mechanism of low-temperature flue gas on activated carbon was reviewed in this work, and three denitration mechanisms were described in detail, namely physical adsorption, chemical adsorption and selective catalytic reduction (SCR) reactions. The oxidation as a result of the presence of oxygen in flue gas can effectively improve the denitration efficiency of flue gas on activated carbon. However, the competitive adsorption of SO2, H2O, and NO in flue gas can reduce the denitration performance of activated carbon. The inhibition and influence of SO2 and H2O on the denitration of low-temperature flue gas over activated carbon was also discussed. Chemical modification of activated carbon loading transition metal oxides and rare earth metal oxides and their effect on the activity of activated carbon were described. The mechanism of activity improvement of activated carbon loading transition metal oxides and rare earth metal oxides was also reviewed. The loading of multi-metals oxides on activated carbon and their synergistic effects on performance improvement of activated carbon were also introduced. Finally, the research direction and the industrial application of low-temperature denitration technology of sintered flue gas on activated carbon were prospected.

Key words: Denitration, activated carbon, absorption, selective catalytic reduction

摘要： 烧结烟气氮氧化物(NOx)排放占钢铁行业NOx排放总量的50%以上，随着环保法规的日益严格，现有及新建烧结机只有装设烟气脱硝装置才能满足排放法规的NOx排放要求。而活性炭微孔丰富、比表面积大、吸附能力强，低温时即可同时脱除烟气中的SO2, NOx、粉尘及其他有害气体。因此，低温烧结烟气活性炭脱硝具有显著的特点及技术优势，但活性炭脱硝易受烟气中SO2和H2O的影响。本工作综述了低温烟气活性炭脱硝机理，主要包括物理吸附、化学吸附及选择性催化还原反应。烟气中氧气的存在起氧化作用，能有效提高活性炭的脱硝率；而SO2, H2O和NO存在竞争吸附作用会降低活性炭的脱硝性能，详述了SO2和H2O对活性炭脱硝的抑制作用及影响。阐述了活性炭负载过渡金属、稀土金属等金属氧化物化学改性对脱硝性能的促进作用及其脱硝机理，并对多元金属的负载进行了介绍；最后对烧结烟气活性炭低温脱硝技术进行了展望。

关键词: 脱硝, 活性炭, 吸附, 选择性催化还原