| 喻瑞,朱繁,史光,崔俊明,张维萍.Nb对MnTiOx在烧结烟气的NH3-SCR低温催化活性及抗钾毒化的促进作用[J].分子催化,2024,38(5):427-436 |
| Nb对MnTiOx在烧结烟气的NH3-SCR低温催化活性及抗钾毒化的促进作用 |
| Promotion Effect of Nb-modification of MnTiOx Catalysts in Low-temperature NH3-SCR Reactivity and K-resistant |
| 投稿时间：2024-05-07 修订日期：2024-06-17 |
| DOI：10.16084/j.issn1001-3555.2024.05.004 |
| 中文关键词: NH3-SCR 低温活性 抗钾中毒 MnTiOx氧化物 Nb改性 |
| 英文关键词:NH3-SCR low-temperature reactivity K-resistance MnTiOx metal oxide Nb-modification |
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| 中文摘要: |
| 钢铁行业的烧结烟气中存在大量的氮氧化物(NOx), 严重破坏环境, 并威胁人类健康. 目前NOx脱除(DeNOx)最有效的方法是氨气选择性催化还原法(NH3-SCR). 在众多NH3-SCR催化剂中, MnTiOx催化剂表现出较好的低温活性, 具有较好的烧结烟气脱硝应用前景. 但实际应用中, MnTiOx容易受到以K为代表的碱金属物种的毒化. 因此, 采用Nb针对性地对MnTiOx进行改性, 以提高催化剂的抗碱金属中毒性能. 我们考察了引入不同Nb含量对MnTiOx NH3-SCR反应性能和抗碱金属性能的影响. Nb改性后的MnTiOx催化剂相较于原催化剂, 其反应性能和抗碱金属K中毒的性能均具有显著提高. 结果表明, 当Nb含量较低时, K会在催化剂上形成较为明显的钾锰氧化物物种, 减少催化剂上酸性位点的数量和强度, 并降低Mn4+和活性氧物种的比例, 这是催化剂K中毒后反应活性降低的原因. 引入Nb后, 增加了催化剂的酸性位点、Mn4+和活性氧物种的比例, 并且K中毒之后, 这些物种下降的幅度明显减少, 因此引入Nb后使得催化剂的反应活性和抗碱金属中毒性能大幅提升. |
| 英文摘要: |
| The flue gas from sintering process in the steel industry contains a large amount of nitrogen oxides (NOx), which seriously damages the environment and threatens human health. The most effective DeNOx method is selective catalytic reduction by NH3 (NH3-SCR). Among the numbers of NH3-SCR catalysts, MnTiOx catalyst exhibits excellent low-temperature activity and has good prospects for DeNOx of sintering flue gas. However, in actual application, MnTiOx is very sensitive to alkali metal (e.g. K) poisoning. Therefore, in this paper, MnTiOx was modified by Nb to improve the resistance of alkali metal K poisoning. This paper investigated the effect of different Nb content on the NH3-SCR reaction performance and K-resistance of MnTiOx. The Nb-modified MnTiOx catalysts showed significantly higher low-temperature NH3-SCR performance and alkali metal K-resistance than the original catalyst. The results suggested that when the Nb/Ti mole ratio was less than 0.04, K-poisoning formed obvious K-Mn oxide species on the catalyst, reducing the number and strength of acidic sites, and decreasing the proportion of Mn4+ and active oxygen species, which might be responsible for the decreased reaction activity after K poisoning. Nb-modification increases the number and proportion of acidic sites, Mn4+, and active oxygen species on the catalyst, and the decrease of these species after K poisoning is significantly reduced, which leads to the improvement of the reaction activity and resistance to alkali metal K poisoning of the MnTiOx catalysts after Nb-modification. |
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