NH3-SCR脱硝催化剂现状及中毒失活现象研究进展

随着国家能源深度调峰的推进并降低锅炉负荷运行，发现锅炉出口烟温难以驱动选择性催化还原脱硝反应的问题，通过综述氨选择性催化还原反应（NH₃-SCR）催化剂在国内外的研究进展，发现单一贵金属催化剂温度窗口窄、易中毒和比表面积较小等问题影响了其催化活性，而复合的金属氧化物催化剂、新兴的生物炭催化剂和沸石催化剂具有多孔性和良好的稳定性等优点。催化剂脱硝机理可以简单表示为其表面的酸性位点吸附氨气和氧气并与之反应，催化剂的中毒原因可总结为其内部空隙被碱金属堵塞、金属氧化物被二氧化硫抢先反应和酸性位点被羟基覆盖，具体表现为催化剂的活性降低、吸附NH₃的效率下降。对比了商用催化剂和新兴催化剂的脱硝性能得出结论，未来的研究方向是研发耐硫、耐水、耐碱的低温高效脱硝催化剂。

Current situation of NH3-SCR denitration catalyst and research progress on poisoning and deactivation

With the promotion of national energy deep peak shaving and the reduction of boiler load operation，it is found that the flue gas temperature at the outlet of the boiler is difficult to drive the selective catalytic reduction denitration reaction.By summarizing the research progress of NH₃-SCR denitration catalyst at home and abroad，it was concluded that the single noble metal catalyst had the factors affecting its catalytic activity，such as narrow temperature window，easy poisoning characteristics and small specific surface area，while the composite metal oxide catalyst，the new biochar catalysts and zeolite catalysts had the advantages of porosity and good stability.The denitration mechanism of the catalyst could be simply expressed as that the acidic sites on its surface adsorbed gaseous NH₃ and O₂ and react with them.The poisoning causes of the catalyst could be summarized as that its internal voids were blocked by alkali metals，metal oxides were preempted by SO₂ and the acidic sites were covered by hydroxyl groups.Specifically，the activity of the catalyst was decreased and the efficiency of NH₃ adsorption was decreased.By comparing the denitration performance of commercial catalysts and emerging catalysts，it was concluded that the future research direction was to develop low-temperature and high-efficiency denitration catalysts with sulfur resistance，water resistance and alkali resistance.