锰负载钛锆和钛锡复合氧化物催化剂烟气脱汞实验研究

采用共沉淀法制备了TiO_2、TiZr和TiSn载体,浸渍锰制备了10%MnO_2的MnTi、MnTiZr和MnTiSn催化剂。采用BET、XRD、H_2-TPR、FT-IR和XPS等对样品进行表征,并对三种催化剂进行固定床脱汞性能实验。结果表明,在100-300℃,MnTiZr和MnTiSn催化剂脱汞性能均优于MnTi催化剂,这归因于Sn和Zr的引入提升了催化剂比表面积和低温氧化还原性能增加了催化剂表面的酸性位点数量、高价态锰离子和O~*含量;在反应温度为150-300℃,MnTiSn催化剂脱汞效率均高于MnTiZr催化剂这是由于前者具有更好的氧化还原性能,表面具有更多含量的高价态锰离子、O~*含量和酸性位点数量;在Hg~0脱除过程中催化剂表面活性组分如高价态锰离子和O~*均消耗,参与了Hg~)氧化为Hg~(2+)的反应且MnTiSn催化剂表面活性组分的消耗量更多。

Experimental study on the mercury removal from flue gas using manganese modified titanium-zirconium and titanium-tin composite oxide catalysts

In this study, TiO₂, TiZr and TiSn supports were prepared using co-precipitation method, and MnTi, MnTiZr, and MnTiSn catalysts with MnO₂ content of 10%were prepared by the wet impregnation method. BET, XRD, H₂-TPR, FT-IR, and XPS were employed to characterize the prepared samples. The Hg⁰ removal performance tests over the three catalysts were conducted in a fixed-bed reactor apparatus. The results indicated that the Hg⁰ removal performance of MnTiZr and MnTiSn catalysts was better than that of MnTi catalyst in the temperature range of 100-300℃. This could be attributed to the introduction of Sn and Zr, which increased the specific surface area of the catalyst, improved the low-temperature redox performance of the catalyst, and elevate the number of acid sites, the high valence manganese ions concentration and O^* content on the catalyst surface. The mercury removal efficiency of the MnTiSn catalyst was higher than that of MnTiZr catalyst at reaction temperature of 150-300℃, which could be ascribed to the higher redox performance of the MnTiSn catalyst and more content of the high valence manganese ions, O^*, and surface acid sites on its surface. During the removal of Hg⁰ in flue gas by MnTiZr and MnTiSn catalysts, active ingredients on the catalyst surface such as high-valence manganese ions and O^* were consumed and participated in the reaction of Hg⁰ oxidation to Hg²⁺. And the consumed amount of active ingredients on the surface of MnTiSn catalyst was more than that on the MnTiZr catalyst.