Ni/CeO_(2)催化剂上CO_(2)甲烷化反应本征动力学研究  

Study on intrinsic kinetics of CO_(2) methanation on Ni/CeO_(2) catalyst

作　　者：范志辉 岳燕燕 张笑楠 李新立 张少康 张振洲 涂维峰 韩一帆 FAN Zhihui;YUE Yanyan;ZHANG Xiaonan;LI Xinli;ZHANG Shaokang;ZHANG Zhenzhou;TU Weifeng;HAN Yifan(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》2024年第8期123-130,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：CO_(2)加氢合成CH4(CO_(2)甲烷化)是CO_(2)高效、清洁转化的重要途径之一。尽管CO_(2)甲烷化的催化体系研究已较深入,但特定条件下CO_(2)甲烷化本征动力学的研究较少。采用燃烧法制备了Ni/CeO_(2)催化剂(Ni质量分数为10%),并通过加入内稀释剂(α-Al_(2)O_(3))制备了不同m(α-Al_(2)O_(3)):m(Ni/CeO_(2))的样品。考察了在温度为300℃、压力为1 MPa和空速为3×10^(6)mL/(g·h)的条件下,m(α-Al_(2)O_(3)):m(Ni/CeO_(2))=25:1样品(样品A)的CO_(2)甲烷化本征动力学。结合本征动力学测试、漫反射红外光谱、H_(2)-程序升温还原和H_(2)-程序升温脱附等对CO_(2)甲烷化本征反应动力学方程进行了深入分析。结果表明,样品A作用下的CH_(4)生成速率最高可达41.4mmol/(g·h)(H_(2)分压为400kPa,CO_(2)分压为120 kPa)。当CO_(2)分压为30~120 kPa时,CH_(4)生成速率随H_(2)分压的增大线性增长,并且不受CO_(2)分压或CO分压变化的影响。在该CO_(2)分压范围内,富氢环境可以显著提高催化剂的CO_(2)甲烷化催化活性。Hydrogenation of CO_(2) to synthesize CH4(CO_(2) methanation)is one of the crucial pathways for the efficient and clean conversion of CO_(2).Despite extensive researches on the catalytic system for CO_(2) methanation,the intrinsic kinetics of CO_(2) methanation under specific conditions have not been thoroughly investigated.Ni/CeO_(2) catalyst(Ni mass fraction of 10%)was prepared using the combustion method,and samples with varying m(α-Al_(2)O_(3)):m(Ni/CeO_(2))were produced by incorporatingα-Al_(2)O_(3) as the internal diluent.The intrinsic kinetics of CO_(2) methanation of sample A with m(α-Al_(2)O_(3)):m(Ni/CeO_(2))=25:1 were examined under the conditions of temperature of 300℃,pressure of 1 MPa and gas hourly space velocity of 3×10^(6) mL/(g·h).An in-depth analysis of the kinetic equations for the intrinsic CO_(2) methanation reaction was conducted through a combination of intrinsic kinetic tests,diffuse reflection infrared spectrum,H_(2)-temperature programmed reaction and H_(2)-temperature programmed desorption,etc.The results show that the CH4 generation rate under action of sample A can reach up to 41.4 mmol/(g·h)(H_(2) partial pressure is 400 kPa,and CO_(2) partial pressure is 120 kPa).When CO_(2) partial pressure is 30 kPa to 120 kPa,the CH_(4) generation rate exhibits linear increases with the rises of the H_(2) partial pressure,and is not affected by variation of the CO_(2) or CO partial pressure.Within this CO_(2) partial pressure range,the hydrogen-rich environment significantly enhances the catalytic activity of the catalyst for CO_(2) methanation.

关 键 词：CO_(2)甲烷化 Ni/CeO_(2)催化剂 本征动力学 

分 类 号：TQ211[化学工程—有机化工] TQ426