Discussion on the deactivation of SCR denitrification catalyst and its reasons
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摘要: 以运行后的蜂窝型SCR（Selective catalytic reduction）催化剂和新鲜催化剂为研究对象。应用红外光谱、氮气吸脱附、X射线衍射、电镜扫描等手段对新鲜催化剂及运行后催化剂进行表征。结果表明，运行后催化剂表面官能团发生了变化，比表面积严重降低，载体（TiO2）产生了型变，并且催化剂表面微粒出现了团聚现象。对运行后催化剂活性降低的原因进行了研究，结果表明，脱硝催化剂在运行过程中遭遇了突发性高温(如t> 650℃)，导致活性出现劣化。此外，催化剂表面沉积物中水溶性离子及砷、磷等物质也对催化活性产生了影响。Abstract: The denitrification behaviors of fresh and used honeycomb SCR catalysts were compared and the deactivation reasons were analyzed by using Fourier transformation infrared spectra (FT-IR), N2 adsorption/desorption, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results show that the functional groups on the surface of the used catalyst are changed and the specific surface area of the used catalyst decreases seriously. Moreover the TiO2 crystallite of used catalyst is changed and some nano-particles aggregate on the surface of the used catalyst. The reason of the deactivation of use catalyst is the unexpected high temperature (e.g. t> 650℃). Otherwise, the water soluble ions, arsenic and phosphorus in the deposit on the surface of the used catalyst can also affect the catalytic activity.
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Key words:
- SCR /
- catalyst /
- deactivation /
- evaluation
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