锑对FCC催化剂上镍的脱氢活性钝化机理的研究

Study On Mechanism of Passivation of Dchydrogenation Activity of Nickel On FCC Catalyst By Passivation Agent Containing Antimony

利用红外光谱法、差热分析等测试手段,对石油催化裂解中的共Y—15FCC催化剂在镍沉积前后,及再经Sb钝化剂处理后的催化剂分别进行了分析考察.由红外光谱对催化剂骨架测定,及用吡啶作探针的酸中心测定,发现镍、锑基本上不破坏催化剂的骨架及酸中心.由DTA图可看到,空白催化剂在200℃～1200℃无任何吸热或放热峰出现.但当镍沉积后,在810℃附近有一放热峰,说明在高温下镍与分子筛有较强的相互作用,估计有NiAl_2O_4生成.当催化剂上有镍及锑沈积后,在530℃、600℃、680℃等处有吸热峰,说明有共熔物及NiSb_2,Ni_4Sb合金生成,这可能是锑钝化剂对镍脱氢产生钝化作用的原因.

The FCC (Flow cracking catalyst) (zcolite-Y-15) before and after deposition of nickel and after deposition of the nickel and antimony has been studied by means of IR spectroscopy and DTA method. The IR spectra demonstrate that the framework construction and acid site of catalyst are almost not destroied by deposition of nickel and antimony. DTA results show that there is not any endothermic or exothermic peak for the blank cata- lyst from 200℃ to 1200℃. After deposition of nickel DTA show exothermic peak near 810℃ and a cndothermic peak near 960℃. Which indicate that there is strong interaction between nickel and catalyst. It seems that NiAl_2O_4 is from. After deposition of nickel and antimony endothermic peak occur near 530℃ 600℃ and 680℃. This shows that cutectic mixture alloy NiSb_2 and Ni_4Sb form. Which can interpret the passivation of dehydrogenation activity of nickel by antimony.