低溫NH3-SCR是排煙溫度低的非電力行業煙氣脫硝的重要技術選擇,低成本、結構可調性好的碳材料是最具潛力的低溫NH3-SCR催化劑之一,但面臨脫硝效率低的瓶頸。本文以低成本、大儲量準東煤為原料,基于一步催化活化工藝制備了具有典型孔隙配組與含氮官能團的活性焦催化劑,探究了活性焦孔隙配組與表面官能團對不同煙氣條件下低溫NH3-SCR的影響。研究結果表明分級孔與含氮官能團對NH3-SCR均有顯著促進作用,兼具分級孔與含氮官能團的氮摻雜分級孔活性焦由于同時改善了傳質通道與反應動力學,具有最優的NH3-SCR性能,160℃條件下的脫硝效率高達83.5%,相比氮摻雜微孔活性焦、無摻雜分級孔焦和微孔活性焦分別提升了14.0%、26.5%和110.9%;在SO2或H2O存在條件下,分級孔和含氮官能團對NH3-SCR性能的提升作用更加明顯,微孔活性焦脫硝效率會由39.6%衰減至13.8%和34.9%,而氮摻雜分級孔焦脫硝效率有所提升,達86.4%和86.7%,這可能與官能化分級孔環境強化不同煙氣組分間的協同效應有關。探明了碳基低溫NH3-SCR性能與碳材料理化結構之間的依存關系,為發展高性能碳基低溫NH3-SCR技術提供了新思路。

Low-temperature NH3-SCR is an important technology choice for flue gas denitrification in non-electricity industries with lowexhaust temperature, and low - cost carbon materials with good structural tunability are one of the most promising low - temperatureNH3-SCR catalysts, but face the bottleneck of low denitrification efficiency. In this paper, based on a one-step catalytic activationprocess, activated coke catalysts with typical pore configurations and nitrogen-containing functional groups were prepared from low-costand large-volume Jundong coal as raw materials, and the effects of activated coke pore configurations and surface functional groups on thelow- temperature NH3 - SCR under different flue gas conditions were investigated. The results showed that both graded pores andnitrogen-containing functional groups have significant effects on NH3 -SCR, and the nitrogen-doped graded-porous activated coke withboth graded pores and nitrogen-containing functional groups has the optimal performance of NH3-SCR due to the simultaneous improvement of the mass transfer channels and reaction kinetics, and its denitrification efficiency reaches as high as 83.5% under the condition of160 ℃ . The enhancement effects of graded pores and nitrogen-containing functional groups on the NH3-SCR performance are more obvious in the presence of SO2 or H2 O, and the denitrification efficiency of microporous activated coke decays from 39.6% to 13.8% and34.9%, whereas the denitrification efficiency of nitrogen - doped graded - porous coke improves to 86. 4% and 86. 7%, respectively.This may be related to the synergistic effect between different flue gas components enhanced by the functionalized graded pore environment.In this study, the dependence between the performance of carbon-based low-temperature NH3 -SCR and the physicochemical structure ofthe carbon materials was investigated, which provides a new idea for the development of high-performance carbon-based low-temperatureNH3-SCR technology.

0 引言

1 試驗

   1.1 材料制備

   1.2 樣品表征

2 結果與討論

   2.1 活性焦理化性質表征

   2.2 分級孔與含氮基團對NOx還原特性的耦合影響

   2.3 SO2對活性焦低溫NOx還原特性的影響

   2.4 H2O對活性焦低溫NOx還原特性的影響

3 結論