钴铁复合修饰FER催化CH4还原NO性能研究

Experiment study on the selective catalytic reduction of NO by CH4 over Fe modified Co-FER catalysts

中文关键词: 选择性催化还原  NO  CH4  镁碱沸石分子筛

英文关键词: FER  NO  CH4  selective catalytic reduction

中文摘要:

      Co系镁碱沸石分子筛在CH4-SCR中表现出较好的潜力,为提高Co-FER的催化活性以及抗水抗硫性能,引入Fe对Co-FER进行改性。采用离子交换法,制备出一系列xFe/Co-FER催化剂,在固定床反应器中进行了CH4选择性催化还原NO实验,并利用N2吸附-脱附、UV-vis、H2-TPR和Py-FTIR等手段进行表征。结果表明,经过适量Fe修饰的Co-FER催化剂能够提高NO转化率、N2选择性以及抗水抗硫性能。0.46Fe/Co-FER在富氧条件下,500°C时NO转化率达到64.9%。加入0.02%SO2后,NO转化率能保持在58.5%左右,加入5%H2O后,仍能保持在54%以上的NO转化率。UV-vis结果表明,0.46Fe/Co-FER中含有更多游离态的Fe3+,因此具有更好的催化活性。H2-TPR结果表明,适量的Fe修饰Co-FER,可以使还原峰向低温移动,提高催化性能。Py-FTIR结果表明,催化剂表面均含有大量的Br?nsted酸和Lewis酸,Fe的引入会显著增加催化剂的Br?nsted酸含量。

英文摘要:

      Co-FER showed good potential in CH4-SCR. In order to improve the catalytic activity of Co-FER and their resistance to water and sulfur, Co-FER was modified with Fe. A series of xFe/Co-FER catalysts were prepared by ion exchange method. The experiment of selective catalytic reduction of NO with CH₄ was tested in a fixed bed reactor. Characterization was carried out by N2 adsorption-desorption, UV-vis, H2-TPR, XPS and Py-FTIR. The results showed that the Co-FER catalyst modified with an appropriate amount of Fe could improve the NO conversion rate, N2 selectivity, and resistance to water and sulfur. 0.46Fe/Co-FER achieved NO conversation of 64.9% at 500°C under oxygen-rich conditions. After adding 0.02% SO2, the NO conversion could be maintained at about 58.5%. After adding 5% H2O, the NO conversion could still be maintained above 54%. The results of UV-vis showed that 0.46Fe/Co-FER contained more free Fe3+, so it showed better catalytic activity. The results of H2-TPR showed that a proper amount of Fe modified Co-FER could shift the reduction peak to low temperature and improved the catalytic performance. Py-FTIR results showed that the catalyst surface contains a large amount of Brφnsted acid and Lewis acid. The introduction of Fe will significantly increased the Brφnsted acid content of the catalyst.