【作者】 任超；

【导师】 任晓光；

【作者基本信息】 北京化工大学 ， 化学工程与技术， 2011， 硕士

【摘要】 NOx是重要的大气污染物之一,对环境的危害很大。选择性催化还原是一种比较有效的消除氮氧化物的方法,近年来得到了广泛的研究。鉴于以纳米二氧化钛为载体的氧化物催化剂具有较高催化活性,六铝酸盐具有较好的热稳定性和较高的催化活性,本文以二氧化钛为载体的氧化物催化剂和六铝酸盐催化剂的制备及它们催化还原NO的活性为主要研究目标。本文采用浸渍法制备了以纳米二氧化钛为载体的不同氧化物活性组分的催化剂；采用共沉淀法制备了不同金属掺杂的锶系六铝酸盐催化剂。用SEM、BET、XRD、H2-TPR等技术对催化剂进行了表征,并用微型反应系统对催化剂的反应活性进行了评价。以NiO/TiO2为探针考察了焙烧时间、焙烧温度、负载量等制备条件对二氧化钛负载金属氧化物催化剂结构和催化性能的影响,得出最佳的制备条件为550℃焙烧4h,最佳的负载量为12%;以SrMnAl11O19-δ为探针考察了焙烧时间、焙烧温度对锶基六铝酸盐催化剂结构和催化性能的影响,得出最佳的制备条件为1200℃焙烧4h。在纳米二氧化钛上负载不同的金属氧化物作为活性组分,考察其结构和催化活性,筛选出结构和活性都较好的活性组分,用筛选出的氧化物在二氧化钛上进行了双活性组分的负载,进行表征和活性评价。结果表明,Fe2O3、NiO、Cr2O3、CuO作为活性组分时,NO的转化率较高。双组分的催化剂中Fe2O3-Cr2O3/TiO2系列催化剂具有来源广、价格低、比表面积大、低温活性好、热稳定性强等特点,是一种性能较好、前景明朗的脱硝催化剂。文中分别将不同的金属离子引入到六铝酸盐进行搀杂,考察其结构和催化活性。铁、钴、镍、铜、铬、锌、锆和铈离子单掺杂制备了SrMAl11O19-δ系列六铝酸盐催化剂,M为铁、钴、镍、铜、铬时,可以形成六铝酸盐结构；当M为Fe、Cu、Cr时,SrMAl11O19-δ催化剂具有很好的NO催化还原活性。用不同量的Fe和Ni掺杂制备了SrMxAl12-xO19-δ系列六铝酸盐催化剂,结果表明,过渡金属只能适量的取代六铝酸盐中的铝,过多的活性金属离子会破坏六铝酸盐的结构。用Mn、Cd、Co、Cu、Fe、Ni、Zn、Zr、Cr和Y双组份复合掺杂制备了SrMNAl10O19-δ系列六铝酸盐催化剂,锰铁、锰镍、锰铬、锰铜、铁钻、铁铜、铜钴复合掺杂可以形成六铝酸盐结构；其中,锰铁、锰铜、铁钻、铁铜、铜钴复合掺杂的六铝酸盐具有很好的NO催化还原活性。选取性能好的组合掺杂制备了SrMnxFe1-xAl11O19-δ、SrFexCo1-xAl11O19-δ、SrFexCo1-xAl11O19-δ、SrFexCu1-xAl11O19-δ、SrCuxCo1-xAl11O19-δ系列催化剂,进行了表征和活性评价。结果表明,SrMnxFe1-xAl11Ol9-δ系列六铝酸盐的结构和催化活性均较好,具有来源广、来源广、价格低、比表面积大、低温活性好、热稳定性强等特点,是一种性能较好、前景明朗的脱硝催化剂。更多还原

【Abstract】 NOx is one of the main air pollutants. The decomposition of NOx has received growing interest because of its environmental effect. The SCR offers an attractive alternative method to reduce industrial NOx emission. Metallic oxide catalyst with TiO2 as carriers is a kind of catalytical materials with higher catalytic activities. Hexaaluminates is a kind of catalytical materials with high thermal stability and higher catalytic activities. In this thesis, the preparation methods of the two kinds of catalysts and theirs activities for SCR-DeNOx were studied.The impregnation methods was employed to prepare metallic oxide catalysts with TiO2 as carriers. The co-precipitation methods was employed to prepare Sr-hexaaluminate catalysts. The catalysts were characterized by means of XRD, BET, TPR, SEM, TG-DTA etc. The performance of the catalysts was investigated by miniature fixed bed reactor with CO+NO as model reaction.Effect of calcination temperature, calcination time, loading factor on the structure and catalytic activities of metallic oxide catalysts were investigated with NiO/TiO2 as model sample. The best calcination temperature is 550℃, the best calcination time is 4 h, The best loading factor is 12%. Effect of calcination temperature, calcination time, on the structure and catalytic activities of Sr-hexaaluminate catalysts were investigated with SrMnAl11O19-δas model sample. The best calcination temperature is 1200℃, the best calcination time is 4h.Lots of metallic oxides were loaded on nano-TiO2.Their structure and catalytic activities were investigated. The metallic oxide catalysts with dual-active component were prepared by the metallic oxide expressed well. Their structure and catalytic activities were investigated. The results showed when active component was Fe2O3、NiO、Cr2O3 or CuO, the conversion of NO was high. The Fe2O3-Cr2O3/TiO2 catalysts expressed smaller larger specific surface area, high thermal stability and higher catalytic activities.In this thesis, Sr-hexaaluminate catalysts were substituted by lots of metallic element. The structure and catalytic activities of substituted hexaaluminate catalysts were investigated. All the catalysts SrMAl11O19-δ(M= Cu, Co, Zn, Fe, Ni, Cr, Zr, Ce) were prepared by the co-precipitation method. The catalysts SrMAl11O19-δ(M= Cu, Co, Fe, Ni, Cr) were found the formation of the crystal phase of hexaaluminates after samples were calcinated at 1200℃for 4 hours. The catalysts SrMAl11O19-δ(M= Cu, Fe, Cr) expressed high catalytic activities. The catalysts SrMAl11O19-δwere prepared. The results showed crystal phase of hexaaluminates would be broken by excessive metallic element.The catalysts SrMNAl10O19-δ(M, N= Mn, Cd, Co, Cu, Fe, Ni, Zn, Zr, Cr, Y) were prepared by the co-precipitation method. In the catalysts substituted by composite metal, the catalysts SrMnFeAl11O19-δ, SrMnCuAl11O19-δ, SrMnCoAl11O19-δ, SrMnCrAl11O19-δ, SrMnNiAl11O19-δ, SrFeCuAl11O19-δ, SrCuCoAl11O19-δ, were found the formation of the crystal phase of hexaaluminates after samples were calcinated at 1200℃for 4 hours; the catalysts SrMnFeAl11O19-δ, SrMnCuAl11O19-δ, SrMnCoAl11O19-δ, SrFeCuAl11O19-δ, SrCuCoAl11O19-δ, expressed high catalytic activities. Then the catalysts SrMnxFe1-xAl11O19-δ, SrFexCo1-xAl11O19-δ, SrFexCo1-xAl11O19-δ, SrFexCu1-xAl11O19-δ, SrMnxCo1-xAl11O19-δ, SrCuxCo1-xAl11O19-δwere prepared. Their structure and catalytic activities were investigated. The results showed SrMnxFe1-xAl11O19-δcatalysts expressed smaller larger specific surface area, high thermal stability and higher catalytic activities.更多还原