活性炭纤维负载铜锆金属氧化物催化脱除NO实验研究

发布时间：2018-05-06 05:26

  本文选题：NOx + 活性炭纤维　； 参考：《河南科技大学》2015年硕士论文

【摘要】：氮氧化物是危害大气的主要污染物之一,其排放已严重威胁着人类赖以生存的环境,并受到越来越广泛的关注。选择性催化还原(SCR)技术是脱除燃煤电厂排放烟气中NOx的应用最广、有效技术之一。近年来低温SCR技术由于具有节能减耗和运行成本低的特点正得到越来越多研究者的关注。从国内外低温SCR技术的研究现状来看,该技术工业化的主要障碍是低温范围内活性不高、催化剂抗毒化性能差、反应机理不明确等问题。针对以上问题,本文使用以活性炭纤维为载体、Cu O和Zr O2作为主要活性成分的催化剂,对其低温SCR脱硝性能进行了较为详细的研究。本文选用浓硝酸处理的活性炭纤维为载体,以Cu O和Zr O2为活性组分,采用浸渍法制备出系列Cu O/ACFN、系列Zr O2/ACFN、系列Cu O-Zr O2/ACFN催化剂。考察了浓硝酸处理活性炭纤维、Cu O与Zr O2单独作为活性组分、Cu O与Zr O2同时作为活性组分以及氧气浓度、氨氮比等反应条件对脱硝活性的影响,并通过比表面积(BET)与孔径分析、X射线衍射(XRD)、扫描电镜(SEM)、热重差热分析(TG-DTA)对催化剂进行分析和结构表征,同时探讨了氧含量、氨氮比等因素对系列催化剂的影响。研究结果表明活性炭纤维经过浓硝酸处理后,比表面积增大了24.338m2/g,吸附量增大;负载Cu O与Zr O2后,催化剂的比表面积随负载量的增加而降低,孔径分析可知,Cu O与Zr O2的负载并未对活性炭的孔隙结构造成明显的影响,与XRD、SEM分析结果一致,Cu O、Zr O2负载量低于0.033Cu O/ACFN、0.025Zr O2/ACFN催化剂时,均为没有明显的Cu O、Zr O2特征峰的出现,活性组分均匀的分布在活性炭纤维表面。结合脱硝活性实验,系列Cu O-Zr O2/ACFN催化剂相比于系列Cu O/ACFN、系列Zr O2/ACFN催化剂在脱硝活性有较大的优势,3:1Cu O-Zr O2/ACFN催化剂在260℃达到最大92%的脱硝效率。氧气能将NO氧化为NO2而促进脱硝反应的进行,但氧气浓度过小或过大时都不利于脱硝反应的进行,经测试氧气浓度为3%时最佳;由脱硝反应机理可知,NH3/NO=1:1,氨氮比过大会导致氧气直接氧化NH3,从而降低脱硝效率,实验结果显示,NH3/NO=1时较为合理。通过本文的系统研究,开发了一种新型的Cu O-Zr O2/ACFN复合氧化物低温SCR催化剂,与现有报道的SCR催化剂相比,该催化剂在低温条件下的催化活性高、成本低等优点,为低温SCR工艺实现工业化应用奠定了基础,为今后低温SCR催化剂的进一步改进提供了指导。
[Abstract]:Nitrogen oxide is one of the main pollutants harmful to the atmosphere. Its emission has seriously threatened the environment on which human beings depend and has been paid more and more attention. Selective catalytic reduction (NOx) is one of the most widely used and effective technologies for removing NOx from flue gas from coal-fired power plants. In recent years, low temperature SCR technology has attracted more and more attention due to its characteristics of energy saving and low operation cost. According to the current research situation of low temperature SCR technology at home and abroad, the main obstacles to industrialization of this technology are low activity in low temperature range, poor antipoisoning performance of catalyst, unclear reaction mechanism and so on. In order to solve the above problems, the low temperature SCR denitrification performance of activated carbon fiber (ACF) supported by CuO and ZrO 2 catalysts was studied in detail. In this paper, a series of Cu O / A CFN, Zr O 2 / ACFN and Cu O-Zr O2/ACFN catalysts were prepared by impregnation method using concentrated nitric acid treated activated carbon fiber as carrier and CuO and ZrO 2 as active components. The effects of concentrated nitric acid treatment on denitrification activity of activated carbon fiber (ACF) treated with concentrated nitric acid, such as Cu O and ZrO 2 as active components, oxygen concentration, ammonia nitrogen ratio and so on, were investigated. The catalysts were characterized by specific surface area (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric differential thermal analysis (TG-DTAA). The effects of oxygen content and the ratio of ammonia to nitrogen on the catalysts were also discussed. The results show that the specific surface area of activated carbon fiber increases by 24.338 m2 / g and the adsorption capacity increases after treatment with concentrated nitric acid, and the specific surface area of the catalyst decreases with the increase of loading amount of CuO and ZrO _ 2. The pore size analysis shows that the loading of CuO and ZrO 2 has no obvious effect on the pore structure of activated carbon. In accordance with the results of XRD SEM analysis, when the loading amount of Cu O 2 O 2 is lower than that of 0.033Cu O / A CFN O 0. 025 Zr O2/ACFN catalyst, there is no obvious characteristic peak of Cu O 2 O 2 O 2. The active components are uniformly distributed on the surface of the activated carbon fiber. Combined with the denitrification activity test, compared with the series Cu O / A CFN, the series of Cu O-Zr O2/ACFN catalysts have a better denitrification activity than the series Cu O / A CFN catalysts. The catalyst 3: 1 Cu O-Zr O2/ACFN has the highest denitrification efficiency of 92% at 260 鈩，

本文编号：1850991