化学链燃烧中LaNi_xFe_(1-x)O_3载氧体的性能研究

Performance of LaNi_xFe_(1-x)O_3 as Oxygen Carriers in Chemical-Looping Combustion Reaction

采用柠檬酸络合法制备了不同Ni含量的LaNixFe1-xO3系列复合氧化物载氧体。采用热分析、X射线衍射、程序升温还原和扫描电境等手段对载氧体进行了表征,并在化学链燃烧反应中进行性能评价。XRD表征结果表明不同Ni含量的LaNixFe1-xO3均能形成钙钛矿结构,TPR表征结果表明随Ni含量增加,LNixaFe1-xO3上氧数量增加,还原能力增强。在连续十次化学链燃烧反应中,95%一氧化碳在LaFe0.5Ni0.5O3上被氧化,扫描电境照片发现部分载氧体颗粒出现破碎、烧结现象。

A series of LaNixFe1-xO3 oxygen carriers with different Ni content was prepared by citric acid complex method,and their properties were characterized by thermal analysis,X-ray diffraction,temperature programmed reduction and scanning electron microscopy.The catalytic performances of the prepared samples were investigated in chemical-looping combustion of CO.The XRD results showed that LaNixFe1-xO3 oxides possessed perovskite-type structure.TPR results indicated that the oxidation ability of LaNixFe1-xO3（x0） was stronger than that of LaFeO3.Especially,the sequential redox reaction revealed that LaFe0.5Ni0.5O3 oxide exhibited high oxygen delivery capacity after 10 redox cycles,and CO conversion ratio was above 95% in each cycle.The structure of LaFe0.5Ni0.5O3 oxide did not change obviously after 10 cycles except some little particles formed on big particles due to heat release in the oxidation processes.