铁基催化剂制备流程对CO加氢反应性能的影响  

Effect of Iron-Based Catalyst Preparation Procedure on CO Hydrogenation Performance

作　　者：刘振新 谷孟勇 贾高鹏 刘惠文 赵晨曦 高玉集 邢宇 LIU Zhenxin;GU Mengyong;JIA Gaopeng;LIU Huiwen;ZHAO Chenxi;GAO Yuji;XING Yu(Henan Provincial Key Laboratory of Surface and Interface Science,School of Materials and Chemical Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,China)

机构地区：[1]郑州轻工业大学材料与化学工程学院河南省表界面科学重点实验室,河南郑州450002

出　　处：《石油学报（石油加工）》2024年第4期974-982,共9页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家自然科学基金项目(21571161);郑州轻工业大学基础研究基金项目(CLY2023LiuZhenxin)资助。

摘　　要：采用共沉淀和高温煅烧法制备Al-O-Zn型载体,分别以2种不同制备流程负载铁和钾元素的先钾后铁法和先铁后钾法制备了2种催化剂样品R1和A1。采用XRD、ICP-OES、氮气物理吸附、场发射电子显微镜、二氧化碳化学吸附-程序升温脱附等手段对2种催化剂样品进行表征,并在固定床加压反应器装置上评价了催化剂的CO加氢制备烯烃的反应性能。结果表明:2种样品在结晶相组成、孔织构、微观形貌上均无显著差异,但是在CO_(2)-TPD曲线特征上却具有巨大的差异,样品R1具有近乎对称的高温脱附峰与低温脱附峰,样品A1则以高温脱附峰为主。在温度290~420℃、压力2 MPa、体积空速1500 mL/(g·h)、反应时间4 h的条件下进行CO加氢反应制备烯烃,与催化剂样品A1作用下的结果相比,样品R1作用下C 2烯烃/烷烃摩尔比最大值高约500%、C_(3)烯烃/烷烃摩尔比最大值高约174%、C 4烯烃/烷烃摩尔比最大值高约35%、C=2~C=4烃类选择性最大值高约44%。催化剂的制备流程不同导致催化剂样品表面的碱性位特征发生显著改变,CO_(2)-TPD曲线高温脱附峰与低温脱附峰近乎对称的情况(样品R1)比高温脱附峰为主的情况(样品A1)更能有效抑制加氢,进而影响催化剂对CO加氢反应的烃类选择性。Al-O-Zn type carriers were prepared using coprecipitation plus high-temperature calcination method.Two catalyst samples R1 and A1 with the same chemical composition were prepared by two different processes,i.e.,loading potassium followed by iron and the iron followed by potassium,respectively.Two catalyst samples were characterized using XRD,ICP-OES,nitrogen physical adsorption,field emission electron microscopy,and carbon dioxide chemical adsorption-temperature programmed desorption.The reaction performance of the catalysts for CO hydrogenation to olefins was evaluated in a pressurized fixed bed reactor.The results show that there are no significant differences in crystal phase composition,pore texture and microstructure between the two samples,and significant differences in the CO_(2)-TPD curve characteristics.Sample R1 exhibits nearly symmetrical high-and low-temperature desorption peaks,while sample A1 mainly shows high-temperature desorption peaks.At the temperature of 290—420℃,pressure of 2 MPa,volumetric space velocity of 1500 mL/(g·h)and reaction time of 4 h,CO hydrogenation reaction was carried out to prepare olefins.Compared with the results under the action of sample A1,the maximum molar ratio of C_(2) olefin to paraffin under the action of sample R1 is about 500%higher,that of C_(3) olefin to paraffin is about 174%higher,that of C_(4) olefin to paraffin molar ratio is about 35%higher,and the maximum selectivity to C=2—C=4 hydrocarbons is about 44%higher.Different preparation processes of the catalyst lead to significant changes in the characteristics of basic sites on the surface of catalyst sample.The hydrogenation is more effectively inhibited when the desorption peaks at high and low temperature are nearly symmetric(sample R1)in the CO_(2)-TPD curve,as compared with the case where the desorption peaks at high temperature are dominated(sample A1),thus affecting the selectivity of the catalyst for hydrocarbons in the hydrogenation reaction of CO.

关 键 词：CO加氢 铁基催化剂 制备流程 低碳烯烃 碱性位 烯烃/烷烃摩尔比 

分 类 号：TQ426.64[化学工程]