Cu-SAPO-44分子筛脱硝催化剂的制备与性能

发布时间：2018-03-11 18:02

本文选题：氨选择性催化还原　切入点：Cu-SAPO-44　出处：《济南大学》2015年硕士论文　论文类型：学位论文

【摘要】：氨选择性催化还原(NH3-SCR)技术是目前消除移动源和固定源中排放的氮氧化物(NOx)的主流技术。在消除移动源譬如机动车尾气的NOx中,分子筛脱硝催化剂由于具有优异的催化能力以及较高的水热稳定性而逐渐取代了传统的钒基体系催化剂。尤其是Cu-SSZ-13、Cu-SAPO-34等Cu基小孔结构的菱沸石型(CHA)分子筛催化剂,已经成为近年来分子筛脱硝催化材料的研究热点。由于SAPO-44分子筛同样具有CHA的结构,故本文从研究SAPO-44分子筛的合成方法入手,通过改进合成工艺,使用不同的新型复合模板剂,成功合成出了SAPO-44分子筛以及Cu-SAPO-44分子筛脱硝催化材料,进一步考察了其脱硝性能以及催化剂中活性物种的存在状态。本论文改进合成方法,首次使用四乙烯五胺(TEPA)与N,N,N',N'-四甲基-1,6-己二胺(TMHD)复合模板剂结合的方法成功的合成出了SAPO-44分子筛以及负载不同Cu含量的Cu-SAPO-44分子筛脱硝催化剂。通过对不同的后处理所得到的Cu-SAPO-44分子筛脱硝催化剂进行脱硝性能测试后筛选出了最优催化剂。对催化剂运用X射线粉末衍射(XRD)、N2吸脱附、电感耦合等离子体发射光谱(ICP-AES)、扫描电子显微镜(SEM)、高角环形暗场探针-扫描透射电镜(HAADF-STEM)、X射线吸收精细结构(XAFS)、程序升温还原(TPR)等表征手段分析了活性物种的存在状态与催化活性的关系,最终确定其主要的催化活性位为高度分散的CuO和Cu2+。为了降低Cu-SAPO-44分子筛的合成成本,使用价格低廉的环己胺(CHA)代替了价格昂贵的TMHD,并采用TEPA与CHA复合模板剂结合的方法成功合成出了负载不同Cu含量的Cu-SAPO-44分子筛脱硝催化剂。通过对不同的后处理所得到的Cu-SAPO-44分子筛脱硝催化剂进行脱硝性能测试后筛选出了最优催化剂。最终达到了既降低合成成本又提高了脱硝活性的目的。
[Abstract]:Ammonia selective catalytic reduction (NH _ 3-SCR) technology is the main technology to eliminate nitrogen oxides (no _ x) emitted from mobile and stationary sources. In the elimination of moving sources such as motor vehicle exhaust (NOx), ammonia selective catalytic reduction (NH _ 3-SCR) is the main technology for eliminating no _ x emissions from mobile and stationary sources. Due to their excellent catalytic ability and high hydrothermal stability, molecular sieve denitrification catalysts have gradually replaced the traditional vanadium-based catalysts, especially Cu-SSZ-13 / Cu-SAPO-34 zeolite catalysts. In recent years, molecular sieve denitrification catalyst material has become a hot spot. Because SAPO-44 molecular sieve also has the structure of CHA, this paper begins with the study of the synthetic method of SAPO-44 molecular sieve, through improving the synthetic technology, using different kinds of new composite templating agent. SAPO-44 molecular sieve and Cu-SAPO-44 molecular sieve denitrification catalyst materials were successfully synthesized, their denitrification performance and the existence of active species in the catalyst were further investigated. SAPO-44 molecular sieve and Cu-SAPO-44 molecular sieve denitrification catalyst loaded with different Cu content were successfully synthesized by the method of the combination of tetraethylenepentylamine (Tepa) and N (N) (N (N) N (N)) (N (N)) -tetramethyl-tetramethyl-1-hexamethylenediamine (THD) complex template for the first time. Through different post-treatment, the catalyst for denitrification of Cu-SAPO-44 molecular sieve was prepared. The obtained Cu-SAPO-44 molecular sieve denitrification catalyst was screened out after the denitrification performance was tested. The catalyst was adsorbed and desorbed by X-ray powder diffraction (XRD). Inductively coupled plasma emission spectrometry (ICP-AESN), scanning electron microscopy (SEM), high angle ring dark field probe (STEM), HAADF-STEMU X-ray absorption fine structure (XAFSX), temperature programmed reduction (TPRR) and other characterization methods were used to analyze the existence of active species. In relation to catalytic activity, In order to reduce the cost of synthesis of Cu-SAPO-44 molecular sieve, its main catalytic active sites are highly dispersed CuO and Cu2. The cheap cyclohexylamine (cha) was used to replace the expensive TMHD, and the Cu-SAPO-44 molecular sieve denitrification catalyst loaded with different Cu content was successfully synthesized by the combination of TEPA and CHA composite template. The obtained Cu-SAPO-44 molecular sieve denitrification catalyst was tested for denitrification and the optimum catalyst was selected, which can reduce the synthesis cost and increase the denitrification activity.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;X734.2

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