新型金属型钝镍剂的开发与研究

以CHZ 2催化裂化平衡剂为钝镍对象 ,对优选出的稀土和碱土金属钝镍剂的钝镍效果进行了评价。结果表明 ,稀土和碱土基钝镍剂对平衡催化剂上的沉积镍具有明显的钝化效果。钝镍剂的加入量有一个最佳值 ,适量的钝镍剂除了能钝化镍的脱氢作用 ,还能调节催化剂表面的酸结构。采用X 射线衍射、程序升温还原实验、X光电子能谱等方法对钝镍机理的研究表明 ,在制备过程中 ,沉积镍与稀土金属元素相互作用生成了稳定性高的RENiO3 物相 ,而与碱土金属离子发生晶格取代反应并形成固溶物 ,使镍处于难以还原的高价态 ,封闭了镍的脱氢活性。在相同的还原条件下 ,经钝镍剂处理过的样品中Ni2 P3/ 2 结合能均高于未进行钝镍处理的样品 ,这说明加入钝镍剂后 ,改变了镍的电子特性 ,使镍处于低脱氢活性的高价氧化态

DEVELOPMENT OF A NEW TYPE OF METAL PASSIVATORS AND CORRESPONDING MECHANISMS OF PASSIVATING NICKEL

Two types of metal passivators for resisting nickel contamination are successfully designed, taking RE (rare earth) and AE (alkaline earth) as effective elements. The corresponding mechanisms of passivating nickel are studied by means of XRD, TPR, XPS and NH-3|TPR methods. The new types of passivation agents can effectively suppress the dehydrogenation activity of nickel and improve the catalytic properties of the FCC catalysts. The study reveals that nickel deposits on the FCC catalysts can interact strongly with elements of RE and AE based passivators under FCCU regenerator condition to produce stable compound of RENiO-3 and solid solution of the crystalline substitution between Ni 2 and AE 2 metal ions respectively. The addition of passivation agents alters the electronic properties of nickel and makes nickel difficult to be reduced.