新型合成气甲烷化催化剂La2O3-ZrO2-Ni/Al2O3的制备与性能  

Preparation of a novel catalyst of La2O3-ZrO2-Ni/Al2O3 and its performance in syngas methanation

作　　者：李春启[1] LI Chunqi(Datang International Chemical Technology Research Institute Co.,Ltd.,Beijing 100070,China)

机构地区：[1]大唐国际化工技术研究院有限公司

出　　处：《化工进展》2019年第6期2776-2783,共8页Chemical Industry and Engineering Progress

摘　　要：针对常规合成气甲烷化催化剂高热结构稳定性差、活性低、适应性差等不足,本文创新地引用稀土金属氧化物La2O3复配过渡金属氧化物ZrO2作为多功能复合助剂,利用反向沉淀法制备了新型合成气甲烷化催化剂La2O3-ZrO2-Ni/Al2O3,同时制备催化剂Cr2O3-Ni/Al2O3作为参照组。采用X射线衍射(XRD)、透射电子显微镜(TEM)表征了催化剂的微观结构,并利用N2吸附仪(BET)测量催化剂经高温水热处理前后的微孔结构参数,以考察催化剂的高热结构稳定性。结合国内某大型煤制天然气项目工艺特征和运行实践,应用Aspen Plus软件模拟了四段甲烷化工艺理论平衡值。基于自主固定床合成气甲烷化评价实验装置,考察了反应压力、空速和原料气H2O(g)含量等因素对La2O3-ZrO2-Ni/Al2O3催化性能的影响,并开展了1000h长周期寿命评价实验。结果表明,La2O3-ZrO2-Ni/Al2O3比Cr2O3-Ni/Al2O3具有更优的高热结构稳定性;可使CO和CO2反应达到或接近催化剂床层出口温度下的理论平衡状态,呈现显著的宽温活性;活性组分NiO晶粒尺寸介于7~10nm,分散度较高;对反应压力、空速和原料气H2O(g)含量的变化不敏感,具有良好的操作弹性;1000h反应后仍能保持较高的活性和稳定性。To overcome the limit of syngas methanation catalyst in thermal stability, activity or suitability, a novel catalyst, La2O3-ZrO2-Ni/Al2O3, was prepared using La2O3-ZrO2-Ni/Al2O3 as multi-functional additive. Meanwhile, another catalyst of Cr2O3-Ni/Al2O3, was also prepared for reference. Then the microstructure of the catalyst was characterized by using X-ray diffraction(XRD) and transmission electron microscope(TEM). The micropore parameters were determined by using N2-adsorption(BET)method. And the theoretical equilibrium values of the four-stage methanation process adopted by a certain SNG plant were simulated by using Aspen Plus. Furthermore, the influence of pressure, space velocity and H2 O(g) content on the catalyst performance were investigated, and the 1000 h life assessment was also conducted. The results show that La2O3-ZrO2-Ni/Al2O3 is superior to Cr2O3-Ni/Al2O3 in thermal stability and temperature activity, which helps the conversion of CO and CO2 approaching to the simulated equilibrium values. The active component, NiO, is well dispersed, with the particle sizes in the range of 7-10 nm. The performance of La2O3-ZrO2-Ni/Al2O3 is insensitive to the changes of pressure, space velocity or H2 O(g) content. Moreover, La2O3-ZrO2-Ni/Al2O3 could preserve its high activity and stability after running for 1000 h.

关 键 词：合成气 甲烷化 合成天然气 催化剂 LA2O3 ZRO2 CR2O3 NI/AL2O3 

分 类 号：O643[理学—物理化学]