Ni/Al_(2)O_(3)-CeO_(2)催化剂上乙烷干重整反应本征动力学研究  

Study on intrinsic kinetics of ethane dry reforming reaction on Ni/Al_(2)O_(3)-CeO_(2) catalysts

作　　者：郭冰洋 杜春丽 范志辉 杨旭港 张艺 闫龙飞 张振洲 涂维峰 GUO Bingyang;DU Chunli;FAN Zhihui;YANG Xugang;ZHANG Yi;YAN Longfei;ZHANG Zhenzhou;TU Weifeng(School of Chemical Engineering,Zhengzhou University,Zhengzhou 450001,Henan,China)

机构地区：[1]郑州大学化工学院,河南郑州450001

出　　处：《低碳化学与化工》2025年第3期39-46,共8页Low-Carbon Chemistry and Chemical Engineering

基　　金：国家自然科学基金面上项目(22278379);河南省科技研发计划联合基金(222301420010)。

摘　　要：乙烷干重整反应是实现CO_(2)利用的重要途径之一。Ni基催化剂因具有低成本和高催化活性等特点被广泛用于乙烷干重整反应。然而,乙烷干重整反应机理仍不明晰,这制约了高效Ni基催化剂的开发。采用溶胶凝胶法制备了Ni质量分数分别为5%和10%的Ni基催化剂(5%Ni/Al_(2)O_(3)-CeO_(2)和10%Ni/Al_(2)O_(3)-CeO_(2)),通过本征动力学方法分析了反应物分压(pC_(2)H_(6)和p_(CO)_(2))和产物分压(p_(H_(2))和p_(CO))对相关反应的影响,研究了反应温度、Ni团簇平均粒径对乙烷干重整反应过程中乙烷活化的影响。结果表明,在温度为823 K、常压、pC_(2)H_(6)为0.1~7.0 kPa、p_(CO)_(2)为2.0~20.0 kPa和空速为6.9×10^(5) mL/(g·h)下,催化剂上乙烷正向转化速率与pC_(2)H_(6)线性相关,且不受p_(CO)_(2)、p_(H_(2))和p_(CO)的影响;在本征动力学区间内,乙烷重整反应速率的速率控制步骤为乙烷活化,活化能为(108±10)kJ/mol。在温度为823 K、常压和空速为6.9×10^(5) mL/(g·h)下,Ni团簇平均粒径为6.5 nm的5%Ni/Al_(2)O_(3)-CeO_(2)具有较高的乙烷活化速率((7.26±0.80)mol/(mol·min·kPa))。Ethane dry reforming is one of the important ways to realize CO_(2) utilization.Ni-based catalysts are widely used in ethane dry reforming reactions due to their characteristics of low costs and high catalytic activities.However,the mechanism of ethane dry reforming is still unclear,which restricts the development of high-efficienct Ni-based catalysts.Using the sol-gel method,Ni-based catalysts with nickel mass fractions of 5%and 10%(5%Ni/Al_(2)O_(3)-CeO_(2) and 10%Ni/Al_(2)O_(3)-CeO_(2)),respectively,were prepared.The effects of the reactants partial pressures(pC_(2)H_(6) and p_(CO)_(2))and the products partial pressures(p_(H_(2)) and p_(CO))on the related reactions were analyzed by intrinsic kinetic method.The influences of reaction temperatures and Ni clusters average particle sizes on the activation of ethane during ethane dry reforming were studied.The results show that at temperature of 823 K,atmospheric pressure,pC_(2)H_(6) of 0.1 kPa to 0.7 kPa,p_(CO)_(2) of 2.0 kPa to 20.0 kPa and space velocity of 6.9×10^(5) mL/(g·h),the forward rate of ethane conversion increases linearly with pC_(2)H_(6) while independent with p_(CO)_(2),p_(H_(2)) and p_(CO) over the catalysts.In the intrinsic kinetic interval,the rate-controlled step of the ethane dry reforming reaction rate is ethane activation,and the activation energy is(108±10)kJ/mol.At temperature of 823 K,atmospheric pressure and space velocity of 6.9×10^(5) mL/(g·h),5%Ni/Al_(2)O_(3)-CeO_(2) with Ni clusters average particle sizes of 6.5 nm exhibits relative high ethane activation rate,which is(7.26±0.80)mol/(mol·min·kPa).

关 键 词：乙烷干重整反应 Ni/Al_(2)O_(3)-CeO_(2)催化剂 本征动力学 反应机理 

分 类 号：TQ032[化学工程]