Ni/W-Al_(2)O_(3)催化剂在富氢气体中CO选择性甲烷化的研究

Selective methanation of CO over Ni/W-Al_(2)O_(3)catalyst in hydrogen-rich gas

采用等体积浸渍法在Ni基催化剂上添加W助剂制备Ni/W-Al_(2)O_(3)催化剂,探究Ni负载量、W摩尔分数和焙烧温度对催化剂CO选择性甲烷化的影响。利用XRD、N_(2)-物理吸附、H_(2)-TPR、NH_(3)-TPD、CO_(2)-TPD、TEM等对催化剂进行表征。结果表明,有W的催化剂在低温下活性很差,不能提高活性。在Ni负载量为20%、W摩尔分数为0.05、焙烧温度为900℃、空速为4800 h^(-1)的条件下,反应温度在207~339℃范围内,20%Ni/0.05W-Al_(2)O_(3)-900℃催化剂能使CO出口体积分数始终小于10μL/L,CH_(4)出口体积分数小于2%。

Ni/W-Al_(2)O_(3)catalyst is prepared through equal volume impregnation method with adding W additive onto Ni-based catalyst,and the effects of Ni loading,W content and calcination temperature on CO selective methanation of catalyst are investigated.The prepared catalyst is characterized by means of XRD,N_(2)-physical adsorption,H_(2)-TPR,NH_(3)-TPD,CO_(2)-TPD and TEM.Results show that the catalyst with W has poor activity at low temperature,so the activity cannot be improved.The 20%Ni/0.05W-Al_(2)O_(3)-900℃catalyst can always keep CO concentration at outlet less than 10 ppm and CH_(4)concentration at outlet less than 2%when the loading amount of Ni is 20%,the molar fraction of W is 0.05,the calcination temperature of catalyst is at 900℃,the space velocity is 4800 h^(-1),and reaction temperature is in the range of 207-339℃.