Ti-Al复合载体载锰催化剂同时脱硝脱汞实验

采用溶胶-凝胶法制备了一系列TiO₂、TiO₂-Al₂O₃（TiAl）、MnO₂/TiO₂（MnTi）和MnO₂/TiO₂-Al₂O₃（MnTiAl）样品，在固定床实验装置上研究了MnTi和MnTiAl催化剂的脱硝、脱汞性能，并对相应的样品进行了BET、XRD、H₂-TPR、XPS表征分析。表征结果表明，Al₂O₃掺入TiO₂后能极大提高载体的比表面积，提升催化剂氧化还原性能，且有利于高价态锰离子（Mn³⁺和Mn⁴⁺）和化学吸附氧（O*）在催化剂表面富集。固定床实验结果表明，在反应温度范围内，MnTiAl催化剂脱硝、脱汞性能均优于MnTi催化剂，MnTiAl催化剂在200℃时脱硝、脱汞效率分别高达88.5%和96.1%。MnTiAl脱除烟气Hg⁰过程中，将Hg⁰氧化为Hg²⁺的同时，催化剂表面Mn³⁺、Mn⁴⁺和O*浓度均被消耗，同时烟气中的O₂能将催化剂表面较低价态的锰离子（Mn²⁺和Mn³⁺）重新氧化为高价态锰离子（Mn³⁺和Mn⁴⁺），并且能补充催化剂表面的化学吸附氧（O*），进而实现催化剂催化氧化Hg⁰过程。

Experimental on simultaneous NO and mercury removal over manganese modified Ti-Al composite catalyst

Sol-gel method was applied to synthesize TiO₂, TiO₂-Al₂O₃ (TiAl), MnO₂/TiO₂ (MnTi), and MnO₂/TiO₂-Al₂O₃ (MnTiAl). The simultaneous removal of NO and Hg⁰ from the coal-fired flue gas over MnTi and MnTiAl catalysts were studied on a fixed-bed reactor system, and the corresponding samples were characterized and analyzed by BET, XRD, H₂-TPR, and XPS. The characterization results showed that the introduction of Al₂O₃ into TiO₂ could greatly increase the specific surface area of the support, improve the redox performance of the catalyst, and promote the enrichment of high-valence manganese ions (Mn³⁺ and Mn⁴⁺) and chemisorbed oxygen (O*) on the catalyst surface. The results of the reaction experiments showed that the MnTiAl catalyst exhibited better NO and Hg⁰ removal performance than the MnTi catalyst in the entire reaction temperature range. The efficiencies of denitrification and mercury removal by MnTiAl catalyst at 200℃ were as high as 88.5% and 96.1%, respectively, and the concentration of Mn³⁺, Mn⁴⁺, and O* on the surface of the catalyst were all consumed along with the oxidization of Hg⁰ to Hg²⁺. At the same time, the O₂ in the flue gas could re-oxidize the low-valence manganese ions (Mn²⁺ and Mn³⁺) to high-valence manganese ions (Mn³⁺ and Mn⁴⁺), as well as recover and replenish the chemically adsorbed oxygen (O*) species on the surface of the catalyst, thereby realizing the catalytic Hg⁰ oxidation over the MnTiAl catalyst.