CO2/CH4干重整转化催化剂的积碳控制研究

Study of carbon deposition controlling over CO2/CH4 dry reforming catalyst

采用浸渍法制备了一系列Ni负载量和焙烧温度不同的Ni/MgO催化剂,通过干重整反应对催化剂的性能进行评价,采用O2-TPO与CO2脉冲相结合的方法分析了反应后催化剂上积碳的含量,并利用XRD,SEM,H2-TPR,CO2-TPSR等分析方法对反应后催化剂上的积碳进行表征。实验结果表明,反应温度为600℃时催化剂上的积碳最严重,积碳主要为不规则的纳米尺度的石墨结构丝状碳,此温度下反应生成的积碳具有较高的反应活性;降低催化剂Ni负载量和提高焙烧温度均有利于形成NiO-MgO固溶体,增强Ni的分散及其与MgO载体的强相互作用,从而显著削弱Ni中心上CH4解离的反应速率,实现干重整反应过程的积碳控制。

A series of Ni/MgO catalysts with different Ni loading amounts and calcination temperatures were prepared by the impregnation method.The performance of the catalysts was evaluated by dry reforming reactions.The content of the deposited carbon on the catalyst after the reaction was analyzed by O2-TPO combined with CO2 pulses.The deposited carbon on the catalyst after the reaction was characterized by XRD,SEM,H2-TPR,and CO2-TPSR.The results show that when the reaction temperature reaches 600℃,the carbon deposition on the catalyst is the most serious,and the deposited carbon is mainly irregular nano-scale graphite filamentary carbon.The deposited carbon generated at 600℃on the catalyst shows high reactivity.The decrease of the Ni loading amount and the increase of the calcination temperature of the catalyst help form NiO-MgO solid solution and enhance the dispersion of Ni and its strong interaction with the MgO support,which in turn significantly weakens the reaction rate of CH4 dissociation on Ni center and achieves the carbon deposition control in the dry reforming process.