Fe/SAPO-34催化剂制备及其CO加氢制低碳烯烃性能研究  

Preparation of Fe/SAPO-34 catalyst and its performance in CO hydrogenation to light olefins

作　　者：李柳柳 张明伟[1] 汪颖军 房克功[1] LI Liuliu;ZHANG Mingwei;WANG Yingjun;FANG Kegong(State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Chemical Engineering and Technology,Yantai Nanshan University,Yantai 265713,China)

机构地区：[1]中国科学院山西煤炭化学研究所煤炭高效低碳利用全国重点实验室,山西太原030001 [2]中国科学院大学,北京100049 [3]烟台南山学院化学工程与技术学院,山东烟台265713

出　　处：《燃料化学学报(中英文)》2025年第4期504-514,共11页Journal of Fuel Chemistry and Technology

基　　金：国家重点研发计划(2023YFB4103203);山西省自然科学基金(202103021224445)资助。

摘　　要：费托合成是合成气制低碳烯烃的重要途径,但目前存在产物选择性难以控制、碳效低等问题。本工作采用负压浸渍法制备了一系列不同Fe含量的Fe/SAPO-34催化剂,并评价了其CO加氢反应性能。结合N_(2)吸附-脱附、XRD、SEM、NH_(3)-TPD和CO-TPD等表征手段,揭示了不同Fe含量Fe/SAPO-34催化剂的构效关系。结果表明,随着Fe负载量的增加,催化剂表面酸强度和酸量依次降低,CO的非解离活化能力减弱,CO的解离活化能力增强,从而使低碳烯烃和含氧化合物选择性分别呈现升高和下降的变化趋势。在200℃,2.0 MPa,GHSV=3300 h^(-1)的温和反应条件下,在包含CO_(2)的全碳产物分布中,当铁负载量为5%时,低碳烯烃选择性为16.2%,含氧化合物选择性为52.6%;当铁负载量为25%时,低碳烯烃选择性为31.9%,含氧化合物选择性为16.9%。结合in situ IR表征,提出了催化剂上合理的CO加氢反应机制。本研究为高碳效制低碳烯烃催化剂的研制提供了一条新的路径,展现出良好的应用前景。Fischer-Tropsch synthesis is an important route to synthesize light olefins from syngas.However,precise control of the product selectivity and enhancing carbon utilization efficiency remains a challenge.Herein,a series of Fe/SAPO-34 catalysts with different Fe contents were prepared using negative pressure impregnation method,and their performance in CO hydrogenation reaction was evaluated.Combined N_(2)adsorption/desorption,XRD,SEM,NH_(3)-TPD,and CO-TPD characterizations,the structure-performance relationship of the Fe/SAPO-34 catalysts was clarified.The results showed that with the increase of Fe loading,the strength and quantity of the acidity of the catalysts decreased sequentially,while the CO non-dissociation activation ability was weakened and the CO dissociation activation ability was enhanced,resulting in an increasing and decreasing trend in the selectivity of light olefins and oxygenates,respectively.Under a mild reaction conditions of t=200℃,p=2.0 MPa,GHSV=3300 h^(-1),in the carbon products containing CO_(2),the selectivity of light olefins and oxygenates over 5%Fe/SAPO-34 catalyst was 16.2%and 52.6%,respectively;while that over 25%Fe/SAPO-34 catalyst was 31.9%and 16.9%,respectively.A reasonable reaction mechanism was proposed based on the in situ IR characterization.This study provides a new way for the research and development of catalyst for light olefins synthesis with enhanced carbon utilization efficiency,showing promising application prospects.

关 键 词：费托合成 铁基催化剂 SAPO-34分子筛 低碳烯烃 

分 类 号：O643.3[理学—物理化学]