Ag助剂对C_4烃选择加氢Ni基催化剂的影响

采用金属Ni作为C4烃选择加氢活性组分,在一定反应条件(70℃、1.3MPa、液态空速18h-1、n(H2)∶n(C4)=30)下考察了助剂种类(K,Co,Ag,Ce,Mg,Pb,Cu)以及Ag助剂含量对Ni基催化剂选择加氢活性的影响。实验结果表明,Ag助剂能明显提高Ni基催化剂的选择加氢活性,而其他助剂对催化剂的加氢活性没有促进作用,适宜的n(Ni)∶n(Ag)=5。通过XRD,XPS,TPR等手段对催化剂的表征结果显示,Ag助剂能改善催化剂中NiO的分布状态,促进NiO在Al2O3载体表面的团聚,还原后Ag的存在增加了催化剂中Ni晶粒分布的不规整度,从而提高了催化剂的选择加氢活性。

Effect of Ag Promoter on Performance of Ni-Based Catalyst in Selective Hydrogenation of C4 Fraction

Effects of different promoters(K,Co,Ag,Ce,Mg,Pb and Cu) in nickel-based catalysts on selective hydrogenation of C4 fraction were investigated under reaction conditions of 70 ℃,1.3 MPa,LHSV 18 h-1 and mole ratio of hydrogen to oil 30.The results showed that only Ag could significantly enhance activity of the nickel-based catalysts in the selective hydrogenation with the optimum n(Ni) ∶n(Ag) in Ni-Ag/Al2O3 catalyst 5.The Ni-Ag/Al2O3 catalysts were characterized by means of XRD,XPS and TPR.The result indicated that the Ag promoter could improve NiO distribution in the catalysts,promote NiO agglomeration on Al2O3 surface and increase irregularity of Ni crystalline grain distribution after reduction,so activity of the nickel-based catalyst in the selective hydrogenation of C4 fraction increased.