Pt/SO_4^(2-)/ZrO_2-Al_2O_3催化正己烷异构化反应中的失活研究

Deactivation of Pt / Pt/SO_4^(2-)/ZrO_2-Al_2O_3 catalyst for n-hexane isomerization

制备了Pt/SO_4^(2-)/ZrO_2-Al_2O_3(Pt SZA)催化剂,考察了Pt SZA在正己烷异构化反应中的失活与再生问题,并通过XRD、Raman、TG、IR和TPO-MS等手段对失活前后催化剂的晶相、硫质量分数和积碳量进行表征。结果表明:在165℃反应550 min后,Pt SZA催化剂几乎完全失活。失活前后催化剂的晶相结构和硫质量分数没有明显变化,失活催化剂上仅有微量积碳生成,高温氢气和空气再生处理消除了失活催化剂上少量的积碳,催化活性得到完全恢复,催化剂上微量积碳的产生是催化剂失活的主要原因。

Pt/SO_4^（2-）/ZrO_2-Al_2O_3（ Pt SZA） catalyst is prepared. The deactivation and regeneration of Pt SZA catalyst in n-hexane isomerization reaction are studied. The Pt SZA catalyst is characterized by XRD,Raman,TG,IR and TPO-MS technologies to determine the phase,sulfur content and coke content of Pt SZA before and after reaction. The experimental results demonstrate that the Pt SZA catalyst is deactivated in short time,i. e. 550 minutes at 165℃. Compared with the fresh catalyst,the crystalline structure and sulfur content of the deactivated catalyst are almost not changed. The very trace of coke is formed over the deactivated catalyst. The coke deposit on deactivated catalyst can be eliminated by treatment in hydrogen or air at high temperature. The activity of the catalyst can be completely recovered. The main deactivation reason of Pt SZA should be related with the slight coke formed over the catalyst during isomerization reaction.