Preparation of layered K/Mg-Fe-Al catalysts and its catalytic performances in CO hydrogenation

被引:0
|
作者
Zhang J.-L. [1 ]
Wang X. [1 ]
Ma L.-P. [1 ]
Yu X.-F. [1 ]
Ma Q.-X. [1 ]
Fan S.-B. [1 ]
Zhao T.-S. [1 ]
机构
[1] State Key Laboratory of High-efficiency Coal Utilization and Green Chemical Engineering, Ningxia University, Yinchuan
来源
Zhang, Jian-Li (zhangjl@nxu.edu.cn) | 1600年 / Science Press卷 / 45期
基金
中国国家自然科学基金;
关键词
CO hydrogenation; Fischer-Tropsch synthesis; K/Mg-Fe-Al catalyst; Light olefins;
D O I
10.1016/s1872-5813(17)30066-x
中图分类号
学科分类号
摘要
A series of K promoted K/MgFeAl-HTLcs catalysts with different Mg/Fe/Al molar ratios were prepared by means of coprecipitation and impregnation method for direct synthesis of light olefins from CO hydrogenation. The samples were characterized by XRD, N2 adsorption-desorption, SEM, TG, H2-TPR and XPS measurements. The results show that MgFeAl-HTLcs catalyst precursors has typical layered structure. MgO, Fe2O3 and small amount of MgFeAlO4 are formed after calcination. MgCO3 and Fe3O4 could be observed after reaction, and a little Fe5C2 iron carbide with broad and weak peaks appear simultaneously. Thermal stability of K/MgFeAl-HTLcs is improved due to recovery of hydrotalcite-like structure after K promotion. With increase of Al content, specific surface area of the precursors decreases monotonically after structure reconstruction. Reduction of Fe2O3 to Fe3O4 is inhibited with addition of Al, compared with K/Mg-Fe sample. Fe enrichment before reaction and K enrichment after reaction are observed on secondary calcination samples. During CO hydrogenation, the prepared samples show high activity and C2-4= selectivity with low C5+ weight fraction. C5+ hydrocarbons decrease and olefin selectivity increases with increasing Fe/Al molar ratio. The C5+ decreases from 22.17% to 10.90%, and C2-4= weight content increases from 40.98% to 47.28% on K/1.5Mg-0.67Fe-0.33Al sample compared with that of K/1.5Mg-0.67Fe sample. © 2017, Science Press. All right reserved.
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页码:1489 / 1498
页数:9
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