Effect of different support on the catalytic performance of V-Mo/Ti De-NOx catalyst
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摘要: 选用了两种比表面积的TiO2制备了V-Mo/Ti脱硝催化剂。采用XRD、N2-吸附脱附、H2-TPR、Raman、NH3-TPD、O2-TPD、SO2-TPD对不同催化剂的物理化学性质进行了分析。通过固定床微型反应评价装置,对不同催化剂的脱硝性能进行了考察。通过全尺寸脱硝催化剂中试评价装置,对比了不同催化剂的SO2/SO3转化率。结果显示:V-Mo/Ti脱硝催化剂中,当小比表面积TiO2-A和大比表面积的TiO2-B的质量比为75:25时,催化剂与全用小比表面积TiO2-A制得的催化剂相比,聚合态钒物种的含量降低,催化剂的还原性能提升,酸性略有下降,催化剂的Oα含量明显增加,表明催化剂的脱硝性能增强。继续增加大比表面积TiO2-B的质量比至50%,催化剂的酸性下降明显,导致催化剂的脱硝活性下降。大比表面积的TiO2-B的用量增加可以降低催化剂的SO2/SO3转化率。总体而言,当小比表面积TiO2-A和大比表面积的TiO2-B的质量比为75:25时,制备的V-Mo/Ti脱硝催化剂展示了较优的脱硝效果。
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关键词:
- V-Mo/Ti脱硝催化剂 /
- 载体TiO2 /
- 比表面积 /
- 脱硝性能
Abstract: V-Mo/Ti de-NOx catalysts were prepared by two kinds of TiO2 with different BET surface area. XRD, N2-adsorption, H2-TPR, Raman, NH3-TPD, O2-TPD, and SO2-TPD analysis were used to characterize the physiochemical properties of the different catalysts. The catalytic performances of the catalysts were tested via a fixed-bed micro-reactor, and the SO2/SO3 conversion of the different catalysts were tested through a pilot-scale reactor. The results show that the catalyst prepared by TiO2-A and TiO2-B (75%:25%) possesses lower content of the polymeric vanadate, higher reducibility, relatively lower acidity, and higher Oα amount than that of the catalyst prepared with pure TiO2-A. As a result, the former catalyst exhibits higher catalytic activity. However, the acidity of the catalyst decreases obviously when 50% TiO2-B is used, leading to the decline of the catalytic performance. What is more, the using of TiO2-B can decrease the SO2/SO3 conversion of the catalyst. Overall, the catalyst prepared with 75% TiO2-A and 25% TiO2-B displays the best catalytic performance.-
Key words:
- V-Mo/Ti De-NOx catalyst /
- support TiO2 /
- BET surface area /
- catalytic performance
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表 1 不同催化剂的孔结构分析数据
Table 1. Pore structure data of different catalysts
催化剂 比表面积/(m2·g−1) 孔容/(cm3·g−1) 平均孔径/nm TiO2-A 84.6 0.37 17.3 TiO2-B 245.3 0.42 14.7 Cat-1 70.6 0.31 20.1 Cat-2 75.9 0.35 18.6 Cat-3 86.3 0.39 16.0 表 2 不同催化剂的NH3脱附峰
Table 2. NH3 desorption peaks of different catalysts
催化剂 总峰面积 (β+γ)峰面积/
总峰面积/%出峰位置/ ℃ α β γ Cat-1 2.51 79.9 111.7 233.6 415.4 Cat-2 2.19 77.9 99.6 222.8 410.9 Cat-3 2.00 75.7 98.9 221.5 410.5 -
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