Improved Low-Temperature Activity of V2O5-WO3/TiO2 for Denitration Using Different Vanadium Precursors
Improved Low-Temperature Activity of V2O5-WO3/TiO2 for Denitration Using Different Vanadium Precursors
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DOI：
10.3390/catal6020025
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发表时间：
2016-02-01
期刊：
影响因子：
3.9
通讯作者：
Xu, Guangwen
中科院分区：
文献类型：
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作者：
Gan, Lina;Guo, Feng;Xu, Guangwen
本研究以两种不同钒前驱体的V2O5-WO3/TiO2催化剂为原料，在150 ~ 450℃条件下，用NH3选择性催化还原烟气NO。其中，催化剂A以异氰酸铵（NH4VO3）为初浸法制备，催化剂B以乙酰丙酮钒(VO（acac)(2)）为钒前驱体，采用溶剂热法制备。在实验室固定床反应器中，采用模拟烟气，在气体时空速（GHSV）为40000 h（-1）、NH3/NO摩尔比为0.8的条件下进行脱硝催化评价。没有二氧化硫和烟气中水蒸气在200摄氏度,意识到没有转换为56%的催化剂,但80% B 350 ppm二氧化硫的存在和10卷。%烟气中水蒸气稍微减少了没有转换/催化剂B,和它的活动是稳定在108 - h连续测试温度变化从450度到220度C,通过傅里叶变换红外光谱(ir)、热重(TG)分析,结果表明，在低至220℃的温度下，在催化剂B上，亚硫酸铵或硫酸铵的形成和分解之间可能建立了动态平衡。该催化剂具有较高的钒表面原子浓度和较高的V4+/(V4+ + V5+)比。NH3吸附试验显示b催化剂上有更多的酸性位点。本研究为制备220 ~ 300℃烟气NO SCR性能良好的V2O5-WO3/TiO2催化剂开辟了一条新的途径。
This work tested two V2O5-WO3/TiO2 catalysts with different vanadium precursors for selective catalytic reduction (SCR) of flue gas NO using NH3 at 150-450 degrees C. While catalyst A was prepared using ammonium metavanadate (NH4VO3) through incipient impregnation, catalyst B was made according to the solvothermal method using vanadyl acetylacetonate (VO(acac)(2)) as the vanadium precursor. The catalytic evaluation for denitration was in a laboratory fixed bed reactor using simulated flue gas under conditions of a gas hourly space velocity (GHSV) of 40,000 h(-1) and an NH3/NO molar ratio of 0.8. Without SO2 and water vapor in the flue gas at 200 degrees C, the realized NO conversion was 56% for catalyst A but 80% for B. The presence of 350 ppm SO2 and 10 vol. % water vapor in the flue gas slightly reduced the NO conversion over catalyst B, and its activity was stable in a 108-h continuous test at temperatures varying from 450 degrees C to 220 degrees C. Via fourier transformation infrared spectroscopy (FT-IR) and thermogravimetric (TG) analysis, it was shown that over catalyst B a dynamic balance between the formation and decomposition of ammonium sulfite or sulfate is built possibly at temperatures as low as 220 degrees C. For this catalyst there was a higher surface atomic concentration of vanadium and a higher ratio of V4+/(V4+ + V5+), while the NH3 adsorption test revealed more acidic sites on catalyst B. The study discloses a potentially new approach to prepare a V2O5-WO3/TiO2 catalyst with good performance for SCR of flue gas NO at 220-300 degrees C.