化工学报 ›› 2019, Vol. 70 ›› Issue (8): 3000-3010.DOI: 10.11949/0438-1157.20190318

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Fe x MnCe1-AC低温SCR催化剂SO2中毒机理研究

陈潇雪(),宋敏(),孟凡跃,卫月星   

  1. 东南大学能源与环境学院,能源热转换及其过程测控教育部重点实验室,江苏 南京 210096
  • 收稿日期:2019-04-01 修回日期:2019-06-20 出版日期:2019-08-05 发布日期:2019-08-05
  • 通讯作者: 宋敏
  • 作者简介:陈潇雪(1994—),女,硕士研究生,2296761847@qq.com
  • 基金资助:
    燃煤过程有机污染物排放控制技术(2018YFB0605200)

Mechanism study on SO2 poisoning of Fe x MnCe1-AC catalyst for low-temperature SCR

Xiaoxue CHEN(),Min SONG(),Fanyue MENG,Yuexing WEI   

  1. Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, Jiangsu, China
  • Received:2019-04-01 Revised:2019-06-20 Online:2019-08-05 Published:2019-08-05
  • Contact: Min SONG

摘要:

以活性炭为载体,通过超声辅助浸渍法制备了一系列Fe x MnCe1-AC催化剂,考察了该系列催化剂的低温NH3-SCR脱硝活性,确立了活性最佳的催化剂,并探究了SO2对其脱硝性能的影响。结果表明,Fe0.1MnCe1-AC催化剂低温脱硝活性最高,在120~220℃范围内NO的转化率均在90%以上(无SO2)。此外,在180℃、SO2浓度为429 mg/m3时,该催化剂仍能保持77%左右的脱硝率。通过BET、XRD、XPS、H2-TPR、NH3-TPD、FT-IR、TGA等表征手段对催化剂的SO2中毒机理进行了分析。研究发现,SO2能与NH3及催化剂中金属组分生成硫酸铵盐((NH4)2SO4、(NH4)2SO3)、MnSO4等物质,改变了原催化剂孔道结构并减少了催化剂表面Br?nsted和Lewis酸性位点,抑制了催化剂吸附NH3的能力。更多地,SO2促使催化剂中Mn4+、Ce3+、Fe3+和Fe3+—OH-基团数量下降,表面可还原物质减少,从而降低了催化剂的脱硝活性。

关键词: 选择性催化还原, 活性炭, 催化剂, 氮氧化物, 二氧化硫, 中毒机理

Abstract:

A series of Fe x MnCe1-AC catalysts were prepared by ultrasonic-assisted impregnation method with activated carbon as carrier. The low-temperature NH3-SCR denitrification activity of the catalysts was investigated, and the best activity catalyst was established. The effect of SO2 on its denitration performance was also explored. The results showed that Fe0.1MnCe1-AC catalyst exhibited best denitration efficiency at low-temperature among prepared catalysts, the conversion rate of NO exceeded 90% with the temperature range from 120℃ to 220℃ (no SO2). In addition, the catalyst could maintain NO conversion rate of approximately 77% under the atmosphere of 180℃ and SO2 concentration of 429 mg/m3. The mechanism of SO2 poisoning on the catalyst was characterized with BET, XRD, XPS, H2-TPR NH3-TPD, FT-IR and TGA. It was observed that SO2 could form ammonium sulfate ( (NH4)2SO4, (NH4)2SO3 ), and MnSO4 with NH3 and the metal components in the catalyst, which changed the pore structure of the fresh catalyst and reduced the Br?nsted acid sites and Lewis acid sites on the catalyst surface. These variation made the inhibitory effect on the catalytic adsorption capacity of NH3. Moreover, SO2 also promoted a decrease in the number of Mn4+, Ce3+, Fe3+ and Fe3+—OH- groups in the catalyst, and lessened the surface reducible species, thereby reducing the activity of the catalyst denitration.

Key words: selective catalytic reduction, activated carbon, catalyst, nitric oxide, sulfur dioxide, poisoning mechanism

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