【作者】 罗平；

【导师】 邹建国；

【作者基本信息】 南昌大学 ， 化学工程， 2011， 硕士

【摘要】 随着现代工业的发展和汽车数量的日益增加,大气污染已经成为一个日益严重的全球性问题。氮氧化物(NOx)作为大气主要污染物之一,它的过量排放,对人类健康和自然界的生态平衡构成了巨大威胁。因此,NOx的有效脱除(尤其是催化脱除),是当前大气污染控制领域的研究热点之一。本文以凹凸棒石和稀土化合物氧化钇、氧化镧、碳酸铈等为主要原料,采用共混法制备了系列稀土—凹凸棒石催化剂,并在固定床反应器中对其催化分解NO的活性进行了实验考察。实验筛选制备了La-Ce-Attapulgite和Ce-Y-Attapulgite催化剂,考察了稀土加入量、稀土配比、共混液pH值和活化煅烧温度等制备条件对其催化分解NO活性的影响。并在单因素试验的基础上,分别采用响应面法和正交法对其制备条件进行了优化。实验得出La-Ce-Attapulgite催化剂最佳制备条件为：共混液pH值6.5,稀土加入量3%,稀土质量配比LaxCe(1-x)(x=0.55),煅烧温度409℃。Ce-Y-Attapulgite催化剂最佳制备条件为：共混液pH值7,稀土质量配比CexY(1-x)(x=0.8),稀土加入量3%,煅烧温度375℃。在脱硝反应温度为400℃,空速5000h-1,氧含量5%,NO进口浓度0.08%的实验条件下,其脱硝率分别可达66.58%和69.89%。本文在考察了反应温度、空速、进口气体中NO和O2浓度等反应条件对脱硝过程影响的基础上,对其催化反应动力学进行了初步探讨。结果表明：该反应符合二级反应的特征,NO在活性位上的吸附是可逆的,两个被吸附的NO分子之间的表面反应为整个反应的速率控制步骤。实验采用X射线衍射仪、扫描电镜、红外光谱仪和热重分析仪等现代分析检测技术,对催化剂的组成、表面形态以及特征结构等进行考察和表征。更多还原

【Abstract】 With the development of modern industry and the increasing of vehicles, air pollution has become a serious global problem. As the one of main atmosphere pollutants, Nitrogen oxide has huge threat to human health and ecological balance by its excessive emissions. Therefore, effectively elimination of nitrous oxide, especially the catalytic elimination, is present hot issue in environmental protection research area.In this study, attapulgite, yttrium oxide, the lanthanum oxide and the carbonated cerium were choosed as raw materials. A series of RE-Attapulgite catalysts for NO decomposition were prepared by chemical blending method and their catalytic performance was evaluated in a fixed bed flow reactor.La-Ce-Attapulgite and Ce-Y-Attapulgite catalysts were prepared in this study. Meanwhile, the effects of preparation conditions, including the rare earth content, ratio of La/Ce, pH value of the chemical blending, calcination treatment temperature of the catalysts, on catalytic activity of the catalysts for NO decomposition were investigated. After the single factor experiments, response surface experiment and orthogonal experiment methods were applied to optimize the preparation condition of La-Ce-Attapulgite and Ce-Y-the Attapulgite catalyst, respectively.The obtained results indicated that the optimal conditions of La-Ce-Attapulgite catalyst preparation were 2%, x=0.55, pH 7 and 400℃for the rare earth content, LaxCe(1-X), pH value of the chemical blending and alcination treatment temperature, respectively. And the denitration rate could be up to 66.58% under reaction conditions of 400℃, gas space velocity of 5000 h-1, the flue gas of 0.08% NO and 5.0% O2 balancing by N2. The optimal conditions of Ce-Y-Palygorskite catalyst preparation were 3%, x=0.8,7 and 375℃for the rare earth content, CexY(1-x), pH value of the chemical blending and calcination treatment temperature, respectively, and the denitration rate could be up to 69.89%.The effects of reaction temperature, airspeed, NO and O2 density of waste gas on NO catalytic decomposition were investigated. Based on the above experiments, the catalytic reaction dynamics were preliminary discussed. The results indicated that the react model has the second-level characteristic. NO adsorption on catalyst activeness bits is reversible; the surface reaction of two adsorbed NO molecules is the control speed step.X-ray diffractometer, scanning electron microscope, infrared spectrometer and thermogravimetric technology were used to analysis the elements, surface morphology and the characteristic structure of the catalysts, respectively.更多还原