Chemical Industry and Engineering Progress ›› 2022, Vol. 41 ›› Issue (2): 759-769.DOI: 10.16085/j.issn.1000-6613.2021-0522

• Industrial catalysis • Previous Articles     Next Articles

EDTA-assisted preparation of highly active catalysts for Fischer-Tropsch synthesis

ZHAO Xiao(), CHEN Zhongshun, TANG Zhongqiang, SHI Xuan, DAI Chengyi(), MA Xiaoxun()   

  1. School of Chemical Engineering, Northwest University, International Science and Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Shanbei Energy and Chemical Industry Development, Xi’an 710069, Shaanxi, China
  • Received:2021-03-15 Revised:2021-05-21 Online:2022-02-23 Published:2022-02-05
  • Contact: DAI Chengyi,MA Xiaoxun

EDTA辅助制备高活性费托合成催化剂

赵潇(), 陈中顺, 唐忠强, 石轩, 代成义(), 马晓迅()   

  1. 西北大学化工学院,国家碳氢资源清洁利用国际科技合作基地,陕北能源先进化工利用技术教育部工程研究中心,陕西省洁净煤转化工程技术研究中心,陕北能源化工产业发展协同创新中心,陕西 西安 710069
  • 通讯作者: 代成义,马晓迅
  • 作者简介:赵潇(1995—),男,硕士研究生,研究方向为合成气转化。E-mail:1421274879@qq.com
  • 基金资助:
    国家重点研发计划(2018YFB0604901);国家自然科学基金(21706210)

Abstract:

Fischer-Tropsch synthesis (FTS) is crucial for the conversion of natural gas, coal and biomass to clean fuels and value-added chemicals. Traditionally, the iron catalysts for FTS are mainly supported on alumina and silica. However, the interaction between metal and support hindered the formation of active phase iron carbide, resulting in low activity of the catalyst. In this study, Fe/Al2O3 catalyst was prepared by EDTA complex impregnation and the dispersion of iron species on alumina support was improved by coulomb interaction between positively charged hydroxyl (OH2+) and [Fe(EDTA)]- complex anion. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), specific surface area (BET), in situ infrared (in-situ IR) and other means were used. The results showed that the addition of EDTA could enhance the sintering resistance of Fe. In the calcining process, EDTA can be decomposed into small organic molecules, which can reduce the iron species in the catalyst to Fe2+ and thus is conducive to the reduction of the catalyst. Besides, more active centers enhanced the CO adsorption capacity of the catalyst. In-situ IR experiments showed that the catalyst prepared with EDTA enriched the active species easier, which improved the conversion of CO. The product distribution in hydrocarbons was improved by adjusting the content of alkali metal sodium in the system. The Fe-Na/Al2O3 catalyst prepared by EDTA complexation showed high CO conversion (88.5%) and high selectivity of C2~C4= and C5~C11 (total of 71.2%) at a low hydrogen carbon ratio (H2/CO=1/1).

Key words: fixed-bed, syngas, Fischer-Tropsch synthesis, catalyst, hydrocarbons, EDTA

摘要:

费托合成(FTS)对天然气、煤炭和生物质向清洁运输燃料和增值化学品的转化至关重要。传统上,用于FTS的负载型铁催化剂主要是以氧化铝和二氧化硅为载体。然而,金属与载体的相互作用阻碍了活性相碳化铁的形成,使得催化剂活性较低。本文通过乙二胺四乙酸(EDTA)络合浸渍制备了Fe/Al2O3催化剂,通过带正电荷的羟基(OH2+)与[Fe(EDTA)]-配合物阴离子之间的库仑相互作用来提高氧化铝载体上铁物种的分散度。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、比表面积(BET)、原位红外(In-situ IR)等手段进行表征分析。结果表明,添加EDTA有助于增强Fe的抗烧结性。在煅烧络合浸渍制备样品的过程中,EDTA可以分解为具有还原性质的有机小分子,将催化剂中的铁物种还原为Fe2+,有利于催化剂的还原;更多活性中心增强了催化剂对CO的吸附量。原位红外实验表明,EDTA辅助制备的催化剂更容易富集活性物种,从而提高CO的转化率。调节体系中碱金属钠的含量改善了烃内产物分布。在较低的氢碳比(H2/CO=1/1)下,EDTA络合制备的Fe-Na/Al2O3催化剂显示出高的CO转化率(88.5%)以及最大的C2~C4=和C5~C11选择性,总选择性达71.2%。

关键词: 固定床, 合成气, 费托合成, 催化剂, 碳氢化合物, 乙二胺四乙酸

CLC Number: 

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