化工学报 ›› 2018, Vol. 69 ›› Issue (5): 2073-2080.DOI: 10.11949/j.issn.0438-1157.20180019

• 催化、动力学与反应器 • 上一篇    下一篇

MgFeMn-HTLcs的制备、改性及其CO加氢性能

张建利, 王旭, 马丽萍, 于旭飞, 马清祥, 范素兵, 赵天生   

  1. 省部共建煤炭高效利用与绿色化工国家重点实验室(宁夏大学), 宁夏 银川 750021
  • 收稿日期:2018-01-08 修回日期:2018-01-28 出版日期:2018-05-05 发布日期:2018-05-05
  • 通讯作者: 赵天生
  • 基金资助:

    国家自然科学基金项目(21666030);宁夏高等学校一流学科建设(化学工程与技术学科)项目(NXYLXK2017A04)。

Preparation of modified MgFeMn-HTLcs and catalytic performance in CO hydrogenation

ZHANG Jianli, WANG Xu, MA Liping, YU Xufei, MA Qingxiang, FAN Subing, ZHAO Tiansheng   

  1. State Key Laboratory of High-efficiency Coal Utilization and Green Chemical Engineering, Ningxia University, Yinchuan 750021, Ningxia, China
  • Received:2018-01-08 Revised:2018-01-28 Online:2018-05-05 Published:2018-05-05
  • Supported by:

    supported by the National Natural Science Foundation of China (21666030) and the National First-rate Discipline Construction Project of Ningxia (Chemical Engineering and Technology, NXYLXK2017A04).

摘要:

采用沉淀-水热法制备了系列不同Mg/Fe/Mn配比的MgFeMn-HTLcs类水滑石前体,经焙烧、浸渍法K改性用于CO加氢制烯烃反应。采用XRD、SEM、TG、N2吸附-脱附、H2-TPR、XPS等手段对催化剂进行了表征。结果表明,制备的Mg-Fe-Mn前体均具有类水滑石层状结构,Mn的添加使结晶度下降;焙烧后,Mg-Fe样品主要生成MgO,Mg-Fe-Mn样品生成Mg2MnO4、MgO和MgFe2O4物相;反应后主要为MgCO3和FeCO3混合物相,伴随FeO-MnO和FexCy的生成;与K/Mg-Fe样品相比,Mn的加入进一步促进了Fe的分散,使得Fe2O3到Fe3O4还原度增加,其供电子效应促使Fe电子结合能向低偏移。在CO加氢反应中,K/Mg-Fe-Mn催化剂均表现出较高的反应活性和烯烃选择性。其中,K/3Mg-1Fe-2Mn催化剂的效果较好,CH4含量较低,O/P值达5.20,C2=~C4=质量分数为43.03%。

关键词: 费-托合成, 前体, 催化剂, 烃分布, 低碳烯烃, 选择性

Abstract:

A series of MgFeMn-HTLcs (hydrotalcite-like compounds) precursors with different Mg/Fe/Mn molar ratios were prepared by coprecipitation-hydrothermal method, which were then calcined and modified with K impregnation to be used as catalysts for light olefin synthesis from CO hydrogenation. The catalysts were characterized by XRD, SEM, TG, N2 adsorption-desorption, H2-TPR and XPS techniques. The results showed that MgFeMn-HTLcs precursors had typical layered structures of hydrotalcite and reduced crystallinity by Mn addition. After calcination, MgO was only detected from Mg-Fe precursors whereas Mg2MnO4, MgO and MgFe2O4 were co-existed from Mg-Fe-Mn precursors. After CO hydrogenation, main phases were MgCO3 and FeCO3, accompanied by formation of FeO-MnO and little FexCy. Mn addition further promoted Fe dispersion and increased reduction from Fe2O3 to Fe3O4, compared to those of K/Mg-Fe catalysts. With Mn increase and its electron donating effect, binding energies of Fe 2p were shifted to lower values. In CO hydrogenation, all prepared K/Mg-Fe-Mn catalysts showed high activity and C2=-C4= selectivity. O/P value of 5.20 and C2=-C4= fraction of 43.03% were achieved with low methane selectivity over K/3Mg-1Fe-2Mn catalyst.

Key words: Fischer-Tropsch synthesis, precursors, catalyst, hydrocarbon distribution, light olefins, selectivity

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