蜂窝状Ho改性Fe-Mn/TiO2催化剂的制备及其低温选择催化还原(SCR)脱硝性能

Preparation of honeycombed holmium-modified Fe-Mn/TiO2 catalyst and its performance in the low temperature selective catalytic reduction of NOx

  • 摘要: 采用模压法制备了蜂窝状Ho改性的Fe-Mn/TiO2催化剂,研究了结构助剂、黏合剂和造孔剂等对成型催化剂低温选择催化还原(SCR)脱硝性能的影响。优选出一套理想的成型参数:水粉质量比为40%且逐次分批加入;结构助剂玻璃纤维的用量为10%(质量分数);黏合剂羧甲基纤维素的用量为5%(质量分数);助挤剂甘油的添加量为10%(质量分数)且分批加入;造孔剂活性炭粉的用量为2%(质量分数)。该蜂窝状催化剂在120 ℃下脱硝率维持在90%以上,并且在SO2体积分数低于0.02%时具有一定的抗硫抗水性。表征结果表明,成型后蜂窝状催化剂比表面积降低,颗粒分散程度明显减弱,并且表面酸量和表面Mn4+含量下降,对催化活性有一定的影响。

     

    Abstract: A series of honeycombed holmium-modified Fe-Mn/TiO2 catalysts were prepared by moulding method and their performance in the low temperature selective catalytic reduction (SCR) of NOx was investigated. The forming process was optimized as:the mass content of water in the forming additives is 40%, in which 10% structure strengthening agent (glass fiber), 5% binder (carboxymethyl cellulose), 10% squeezing agent (glycerin), 5% pore-forming agent (activated carbon) and a little lubricants (liquid paraffin) are added. The honeycombed Fe-Ho-Mn/TiO2 catalyst prepared under these conditions exhibits excellent performance in the low-temperature SCR of NOx; the conversion of NOx exceeds 90% at 120℃ and a good resistance to SO2 and H2O is observed when the content of SO2 in the stream is lower than 0.02%. The characterization results indicated that in comparison with the parent powder holmium-modified Fe-Ho-Mn/TiO2 catalyst, the honeycombed catalyst exhibits lower surface area, more particle aggregation, and less acid sites and Mn4+ species on the surface, which has a certain negative influence on the catalytic performance of Fe-Ho-Mn/TiO2.

     

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