磷基FCC钝镍剂的开发及应用

Development and Application of Phosphate Salts as Nickel Passivator in FCC

工业试验表明 ,在催化裂化催化剂上的镍污染量高达 1%时 ,环境友好型磷酸盐钝镍剂仍能使汽油收率提高1% ,氢气产率和焦炭产率分别下降 35 %和 10 %以上 ,显示出良好的钝镍效果。结合轻油微反评价 (MAT)、TPR、XRD等实验方法和量子化学计算理论研究 ,阐明了磷基钝镍剂的钝镍机理 :在FCC再生条件 (约 70 0℃ ,氧化性气氛 )下 ,由于磷基钝镍剂热分解生成P2 O5,并与NiO反应生成NiP4O1 1 ,增加了Ni2 + 的能量最低空轨道 (LUMO)能量 ,降低了Ni2 + 在FCC(流化催化裂化 )反应条件 (约 5 0 0℃ ,还原性气氛 )下的还原度 ,有效抑制了Ni0 的强催化脱氢活性 。

The environmental friendly nickel passivator( PPN) consisting of phosphate salts can decrease the yields of hydrogen and coke by 35% and 10% respectively, while increasing the yield of gasoline by 1%. The passivating mechanism of PPN has also been investigated by means of MAT, TPR, TPD, XRD and quantum chemistry methods. The results show that, under the conditions of FCC regeneration, PPN decomposes to form P 2O 5 which reacts with NiO to form the new phase NiP 4O 11 . Because the energy of LUMO of Ni 2+ in NiP 4O 11 is much higher than that of Ni 2+ in NiO, NiP 4O 11 is more difficult to reduce than NiO under the conditions of FCC reaction. Therefore, the catalytic dehydrogenation activity of Ni 0 is inhibited.