【作者】 黄波；

【导师】 江志东；

【作者基本信息】 上海交通大学 ， 化学工程（专业学位）， 2020， 硕士

【摘要】 煤矿开采过程中有大量煤矿瓦斯随矿井排风释放,其甲烷浓度很低,难被直接利用。催化燃烧是低浓度甲烷的有效处理方式。本文用球磨法制备了MgAl₂O₄镁铝尖晶石负载的NiO催化剂用于低浓度甲烷催化燃烧,考察了镍源、NiO负载量、球料比、球磨转速、焙烧温度以及助剂对催化剂性能的影响,并用H₂-TPR、BET、XRD、SEM等仪器对催化剂进行表征。研究发现,与沉淀-沉积法或浸渍法相比,球磨法制备的催化剂前驱体与载体的相互作用较弱,焙烧后形成了催化活性更高的自由态NiO物种。球磨法制备时,镍盐种类影响NiO物种的晶粒尺寸,NiO负载量影响其在载体表面的分布情况,球料比和球磨转速影响催化剂的颗粒大小,焙烧温度改变活性组分与载体表面的相互作用强度。经过对比,以乙酸镍为镍源、NiO负载量10wt.%、球料比2:1、球磨转速400 rpm、经700℃焙烧,制得的NiO/MgAl₂O₄催化剂活性和稳定性较好;600℃下测得拟一级反应速率常数k₆₀₀为0.489 L/（g·s）,高于MgAl₂O₄尖晶石负载的La_0.8Ca_0.2FeO₃或La_0.8Sr_0.2MnO₃钙钛矿催化剂。为提升催化剂耐硫性能,将Pt、Co、Mo等助剂掺杂进入催化剂,发现助剂通过改变NiO物种的状态来影响催化剂性能。经过制备工艺上的优化,NiO/MgAl₂O₄催化剂的活性和稳定性显著提高,在低浓度甲烷催化燃烧的应用中具有突出的优势。更多还原

【Abstract】 A large amount of coal mine methane is released with mine ventilation in the process of mining.Methane in the gas is highly diluted so it is difficult to be treated directly.Catalytic lean burn is an appropriate method for treatment on high-diluted methane.In this paper,NiO catalysts supported on MgAl₂O₄ spinel were prepared by ball-milling method and applied on catalytic lean burn of high-diluted methane.The effects of Ni source,NiO loading,ball-to-powder ratio,ball-milling speed,calcination temperature and additives on catalysts were investigated with instruments like H₂-TPR,BET,XRD,and SEM,etc.Weaker interaction between the Ni precursor and carrier was found in catalysts prepared by ball-milling than by impregnation or deposition-precipitation,to produce the NiO species with higher catalytic activity after calcination.In ball milling,it was found that Ni sources alter the grain size of NiO and NiO loading affects its distribution on the surface of carrier.The size of catalyst particles is influenced by ball-to-powder ratio and ball-milling speed.Then the calcination temperature can change the strength of interaction between active components and carrier.By comparison,the NiO/MgAl₂O₄ catalyst prepared from nickel acetate with 10wt.%NiO loading,ball-milled at ball-to-powder ratio of 2:1 and speed of 400 rpm,and calcined at 700℃has demonstrated better activity and stability,and its pseudo first-order reaction rate constant at 600℃was 0.489 L/（g·s）,which is higher than that of La_0.8Ca_0.2FeO₃ or La_0.8Sr_0.2MnO₃ perovskite supported on MgAl₂O₄ spinel.To improve sulfur resistance of catalysts,additives such as Pt,Co and Mo were doped into the catalysts.They were found to change the state of NiO species,leading to the change of catalytic performance.The optimization of preparation conditions significantly increased the activity and stability of NiO/MgAl₂O₄ catalysts,which have outstanding advantage on catalytic lean burn of high-diluted methane.更多还原