砷对商业V_2O_5-WO_3/TiO_2催化剂脱硝性能的影响

Effect of arsenic on de-NO efficiency over commercial V_2O_5-WO_3/TiO_2 catalyst

以某燃煤电厂钒钛基选择性催化还原(SCR)脱硝催化剂为研究对象,在实验室条件下模拟了该催化剂的As中毒,考察了不同浓度的As对催化剂活性的影响,结合H2-TPR、XPS、NH3吸附FT-IR实验分析As对催化剂性能的影响。结果表明催化剂As中毒后,其活性下降,并且As浓度越大,活性下降越明显;催化剂表面的W和Ti的化学形态不受As的影响,而V物种出现多样化;As对催化剂表面的酸性位有一定的影响,使其吸附NH3的Bronsted酸位减少,而对其酸强度和催化反应途径的影响并不显著。

The poisoning effects of As on traditional SCR catalysts based on V2O5-TiO2 used in a coal fired power plant were studied under the laboratory conditions. The catalysts were characterized by means of HE-TPR, XPS and NH3 adsorption FT-IR. The activity of the catalyst decreased after As poisoning, and the higher the concentration of As, the more significant the decrease of catalytic activity. The chemical forms of W and Ti on the surface were not influenced by As, but V presented various states. Arsenic reduced the number of Bronsted acid on the surface, but did not change the acidity and pathway of catalytic reaction significantly.