张晴, 贺拴玲, 张铮, 汪莉. MnOx−FeOy/TiO2−ZrO2−CeO2低温选择性催化还原NOz和抗毒性研究[J]. 工程科学学报, 2020, 42(3): 321-330. DOI: 10.13374/j.issn2095-9389.2019.11.05.002
引用本文: 张晴, 贺拴玲, 张铮, 汪莉. MnOx−FeOy/TiO2−ZrO2−CeO2低温选择性催化还原NOz和抗毒性研究[J]. 工程科学学报, 2020, 42(3): 321-330. DOI: 10.13374/j.issn2095-9389.2019.11.05.002
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ZHANG Qing, HE Shuan-ling, ZHANG Zheng, WANG Li. Low-temperature selective catalytic reduction of NOz and anti-toxicity of MnOx−FeOy/TiO2−ZrO2−CeO2[J]. Chinese Journal of Engineering, 2020, 42(3): 321-330. DOI: 10.13374/j.issn2095-9389.2019.11.05.002
Citation: ZHANG Qing, HE Shuan-ling, ZHANG Zheng, WANG Li. Low-temperature selective catalytic reduction of NOz and anti-toxicity of MnOx−FeOy/TiO2−ZrO2−CeO2[J]. Chinese Journal of Engineering, 2020, 42(3): 321-330. DOI: 10.13374/j.issn2095-9389.2019.11.05.002
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MnOx−FeOy/TiO2−ZrO2−CeO2低温选择性催化还原NOz和抗毒性研究

Low-temperature selective catalytic reduction of NOz and anti-toxicity of MnOx−FeOy/TiO2−ZrO2−CeO2

    摘要
  • 摘要: 用溶胶凝胶法制备TiO2−ZrO2−CeO2（摩尔比4∶1∶1.25）载体，柠檬酸溶液浸渍法进一步负载MnOx及MnOx−FeOy，进而合成了一种Fe掺杂的新型Mn基复合氧化物催化剂，考察其NH3选择性催化还原NO性能及抗硫性能。它在含硫氛围中有良好的低温选择性催化还原（SCR）能力和抗中毒能力，Fe的引入促进了Mn与TiO2−ZrO2−CeO2载体之间的相互作用，增加了催化剂表面Lewis酸性位点的数量。根据X射线光谱分析，Mn4+，Ce4+和吸附的氧的含量明显增加，对提高催化剂的性能非常有利。根据热重分析，在SO2和H2O同时存在的环境下，Fe的存在使硫酸铵和硫酸铈的产生量减少，抑制了锰的硫酸化，进一步提高了催化剂的抗毒性。MnOx（12.5%）−FeOy（0.8）/TiO2−ZrO2−CeO2（4∶1∶1.25）催化剂在180 ℃下，同时通入体积分数10% H2O和125×10−6 SO2 240 min，NOz转化率可保持在75.6%。根据研究成果，新型锰基复合金属氧化物催化剂为进一步探索催化剂的SCR反应和抗毒机理提供了基础，促进了SCR工艺的工业应用。

     

    Abstract: One of the most effective methods for the removal of NOz from industrial flue gas is the technology known as low-temperature selective catalytic reduction (SCR). The main problem limiting the industrial application of catalysts is the need to improve their performances at low temperatures, and the fact that the anti-toxic mechanism of low-temperature denitration catalysts has yet to be explicitly identified. In this study, a TiO2−ZrO2−CeO2 (molar ratio 4∶1∶1.25) carrier was prepared by the sol–gel method, and then loaded the active components MnOx and MnOx−FeOy using the citric-acid-solution impregnation method to synthesize a new type of Fe-modified Mn-based multi-oxidation-state composite catalyst. The performance of this Mn-based composite oxide catalyst was investigated with respect to its NH3-selective catalytic reduction of NO and sulfur resistance. The catalyst exhibits good low-temperature SCR redox ability and anti-poisoning ability in an SO2-containing atmosphere, whereby the introduction of Fe promotes the interaction between Mn and the TiO2−ZrO2−CeO2 (4∶1∶1.25) carrier, and increases the number of Lewis acid sites on the catalyst surface. According to the XPS analysis, the contents of Mn4+, Ce4+, and adsorbed oxygen are obviously increased, which is very advantageous for improving the performance of the catalyst. According to the thermogravimetric analysis, the introduction of Fe reduces the production of ammonium sulfate and ceric sulfate in the atmosphere containing SO2 and H2O, and inhibites the sulfation of manganese. The Fe element thereby increases the anti-toxic ability of the Mn-based multi-oxidation-state composite catalyst. By maintaining the MnOx (12.5%)−FeOy(0.8)/TiO2−ZrO2−CeO2 (4∶1∶1.25) catalyst at 180 ℃, while continuously feeding 10% H2O in volume fraction and 125×10−6 SO2 for 240 min, the NOz conversion rate can be stably maintained at 75.6%. Based on the results of this work, a new type of Mn-based composite oxide catalyst has been developed that provides a foundation for further exploring the SCR reaction of the catalyst and its anti-toxic mechanism to promote the industrial application of the SCR process.

     

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