K-Fe_(3)O_(4)/Ni-AlMCM-41串联催化CO_(2)加氢制高碳烃  

Performance of K-Fe_(3)O_(4)/Ni-AlMCM-41 tandem catalyst for CO_(2) hydrogenation to long-chain hydrocarbons

作　　者：高新华[1] 卢鹏飞 陈国辉 郭新雨 梁洁[1] 马清祥[1] 张建利[1] 范素兵[1] 赵天生[1] GAO Xin-hua;LU Peng-fei;CHEN Guo-hui;GUO Xin-yu;LIANG Jie;MA Qing-xiang;ZHANG Jian-li;FAN Su-bing;ZHAO Tian-sheng(State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学省部共建煤炭高效利用与绿色化工国家重点实验室,宁夏银川750021

出　　处：《燃料化学学报》2021年第4期504-512,共9页Journal of Fuel Chemistry and Technology

基　　金：宁夏自然科学基金(2018AAC02002);国家自然科学基金(21965029,21968025);第四批宁夏青年科技人才托举工程(TJGC2019022);中国科学院“西部之光”(XAB2019AW02)项目资助。

摘　　要：分别采用溶剂热法和离子交换法制备了K-Fe_3O_4与Ni-AlMCM-41介孔材料,串联后用于催化CO_2加氢制高碳烃,采用XRD、 SEM、 TEM、 NH3-TPD、烯烃-TPD、 ICP-OES、 XRF和XPS等手段对催化剂进行了表征,研究了钾含量和Si/Al比对Fe_3O_4/Ni-AlMCM-41串联催化CO2加氢性能影响。结果表明,Fe_3O_4为400-800 nm的球形颗粒,Ni-AlMCM-41是以弱酸为主的介孔材料;CO2首先在K-Fe_3O_4上生成富含低碳烯烃的混合气,然后在Ni-AlMCM-41酸性位点发生聚合、加氢等反应转化为高碳烃。适当的钾含量,可以提高一段反应CO2转化率及低碳烯烃选择性。当0.5%K-Fe_3O_4与NiAlMCM-41(Si/Al=50)相串联时,两段反应器温度分别为320和250°C,在2 MPa、空速为1000 h-1和H2/CO2物质的量比为3的条件下,CO_2转化率达32.9%,CH4选择性为10.9%,高碳烃选择性为49.8%,远高于单一0.5%K-Fe_3O_4催化剂上的12.2%。The K-Fe3O4 and Ni-AlMCM-41 catalysts were first prepared by a solvothermal and ion-exchange methods,respectively;they are then assembled to K-Fe3O4/Ni-AlMCM-41 tandem catalyst for CO2 hydrogenation to long-chain hydrocarbons.The catalyst samples were characterized in detail by means of XRD,SEM,TEM,NH3-TPD,olefin-TPD,ICP-OES,XRF and XPS;the effect of potassium modification and Si/Al ratio on the performance of Fe3O4/Ni-AlMCM-41 tandem catalyst in the hydrogenation of CO2 was investigated.The results illustrate that the Fe3O4 component has a uniform spherical particles in the size range of 400–800 nm,whilst the Ni-AlMCM-41 component displays mesoporous structure,dominantly with weak acid sites on the surface.CO2 is first converted to gaseous products rich in light olefins over the K-Fe3O4 catalyst and the light olefins is then transformed to longchain hydrocarbons by a series of oligomerization and hydrogenation reactions over the acid sites of Ni-AlMCM-41.Appropriate content of potassium can improve the selectivity to light olefins over the Fe3O4 catalyst in the first stage.In particular,for CO2 hydrogenation under 2 MPa and with a space velocity of 1000 h−1 and a H2/CO2 ratio of 3,when 0.5%K-Fe3O4(320°C)is connected with Ni-AlMCM-41(Si/Al=50)(250°C),the conversion of CO2 reaches 32.9%and the selectivities to CO,CH4,and long-chain hydrocarbons are 7.1%,10.9%and 49.8%,respectively.That is,the selectivity to long-chain hydrocarbons over the K-Fe3O4/Ni-AlMCM-41 catalyst(49.8%)is much higher than that over the single K-Fe3O4 catalyst(12.2%).

关 键 词：CO_2加氢 串联催化 高碳烃 Ni-AlMCM-41 

分 类 号：O643[理学—物理化学]