化工进展 ›› 2021, Vol. 40 ›› Issue (1): 227-233.DOI: 10.16085/j.issn.1000-6613.2020-0427

• 工业催化 • 上一篇    下一篇

CeO2改性再生SCR催化剂的单质汞氧化特性

何川(), 张发捷, 卞子君, 孔凡海, 王乐乐, 吴国勋   

  1. 西安热工研究院有限公司苏州分公司,江苏 苏州 215153
  • 收稿日期:2020-03-20 出版日期:2021-01-05 发布日期:2021-01-12
  • 通讯作者: 何川
  • 作者简介:何川(1988—),男,博士,高级工程师,主要研究方向为大气污染物控制。E-mail:hechuan3333@126.com
  • 基金资助:
    西安热工研究院有限公司自立科技项目(GU-19-TYK02)

Oxidation of elemental mercury by CeO2 modified regenerated SCR catalyst

Chuan HE(), Fajie ZHANG, Zijun BIAN, Fanhai KONG, Lele WANG, Guoxun WU   

  1. Xi’an Thermal Power Research Institute Co. , Ltd. Suzhou Branch, Suzhou 215153, Jiangsu, China
  • Received:2020-03-20 Online:2021-01-05 Published:2021-01-12
  • Contact: Chuan HE

摘要:

对国内某1000MW燃煤发电机组失活选择性催化还原(SCR)催化剂进行CeO2改性再生。对再生前后样品进行N2吸附-脱附、扫描电子显微镜(SEM)、X射线荧光光谱(XRF)、傅里叶变换红外光谱(FTIR)对比表征分析。在自制固定床反应系统上对CeO2改性再生催化剂(CeReCat)进行Hg0氧化性能测试,同时研究了SO2、H2O、NO和NH3对Hg0氧化性能的影响。结果表明,CeO2改性再生方法可有效清洗失活SCR催化剂表面杂质,恢复催化剂表面活性位点和孔隙结构,可使Ce、V两种活性元素得到有效负载。CeO2改性后的样品Hg0氧化性能显著提升,3.0 CeReCat具有最佳Hg0的氧化效率。此外,烟气中加入600μL/L SO2后,3.0 CeReCat仍具有高达74.4%的Hg0氧化效率,抗SO2性能较好。烟气中的NO可轻微促进Hg0的氧化。由于竞争吸附作用,烟气中的H2O和NH3会抑制Hg0的氧化。CeO2改性再生催化剂置于SCR系统下层时,由于烟气NH3浓度较低而具有较高Hg0氧化效率,具有良好的应用前景。

关键词: 烟道气, 催化剂, 氧化, 汞, 选择性催化还原

Abstract:

The deactivated SCR catalyst from a 1000MW coal-fired generating unit in China was regenerated with CeO2 modification. The samples before and after regeneration were characterized by N2 adsorption-desorption, scanning electron microscope (SEM), X-ray fluorescence spectrum (XRF) and Fourier transform infrared spectrum (FTIR). Hg0 oxidation performance of the CeO2 modified regenerated catalysts (CeReCat) were tested on a self-made fixed-bed reaction system, and the effects of SO2, H2O, NO and NH3 on the Hg0 oxidation performance were studied. The results showed that the regeneration by CeO2 modification could effectively remove the impurities on the surface of the deactivated SCR catalyst, restore the surface active sites and pore structure, and simultaneously effectively load Ce and V. The Hg0 oxidation performance of the CeO2 modified samples was significantly improved, and 3.0 CeReCat had the best oxidation efficiency. In addition, when 600μL/L SO2 was added to the flue gas, 3.0 CeReCat still had a high Hg0 oxidation efficiency of 74.4%, indicating a high SO2 tolerance. NO in flue gas slightly promoted the oxidation of Hg0. Due to competitive adsorption, H2O and NH3 in flue gas inhibited the oxidation of Hg0. The CeO2 modified regeneration catalyst exhibited a good application prospect when placed in the lower layer of SCR system where a low NH3 concentration appeared.

Key words: flue gas, catalyst, oxidation, mercury, selective catylitic reduction (SCR)

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