镍系催化剂的制备、表征及其甲烷化性能的研究

采用混合法在球磨机内制备了高温合成气制甲烷的催化剂载体,并添加不同质量二氧化钛和氧化镧助剂对其做了改性,经焙烧成型和负载后进行甲烷化催化反应。表征了成型催化剂的机械强度、BET、氢气程序升温还原（H₂-TPR）、TPD、TG、X射线衍射（XRD）等,并在固定床反应器中评价其甲烷化催化反应性能。结果表明,所制备的催化剂在600 ℃以上,2 MPa条件下可稳定使用,且具有较高的催化活性、抗烧结及抗积炭特性。TiO₂助剂的添加提高了催化剂的机械性能和耐高温性能,而La₂O₃助剂的添加有利于镍在载体表面的分散,增加催化剂的活性,降低了载体的表面酸性,抑制了积炭的产生,因此可以延长催化剂的使用寿命。

Preparation and characterization of nickel-based catalyst and its methanation performance

The catalyst carrier for methane production from syngas at high temperature was prepared in a ball mill by mixing method.The catalyst carrier was modified by adding additives TiO₂ and La₂O₃ with different quality.After calcination and loading,methanation reaction was carried out.The mechanical strength and BET of the catalyst was tested,and the catalyst was also characterized by hydrogen temperature-programmed reduction（H₂-TPR）,TPD,TG and XRD etc.,and its methanation catalytic performance was evaluated in a fixed-bed reactor.The results showed that the prepared catalyst could be used stably under the condition of above 600 ℃ and 2 MPa,and had higher catalytic activity,anti-sintering and anti-carbon properties.The addition of TiO₂ could improve the mechanical properties and high temperature resistance of the catalyst,while the addition of La₂O₃ helped to disperse nickel on the surface of the support,increase the activity of the catalyst,reduce the surface acidity of the support,and inhibit the formation of carbon.Thus,the service life of the catalyst could be prolonged.