助剂Sn对丙烷脱氢制丙烯Pt氧化铝催化剂性能的影响

Effect of Sn on the Performance of Pt/Al_2O_3 Catalyst in Propane Dehydrogenation to Propylene

采用高压浸渍法制备了Pt-Sn/Al2O3催化剂,Pt含量为0.25%,以丙烷脱氢制丙烯的反应评价了催化剂的性能,考察了氧化铝晶型、制备方法、Sn添加量和空速对催化剂性能的影响。结果表明θ型的氧化铝载体比?型氧化铝活性高,?型氧化铝制备的样品活性较低,与常规浸渍法相比,高压浸渍法制备的催化剂活性较高,助剂Sn的添加量对催化剂上丙烷的转化率、丙烯选择性和稳定性具有较大的影响,催化剂的分散度与活性是正相关的,当Pt与Sn的摩尔比为1∶2.5时催化剂活性和分散度最高,转化率为35.6%,选择性大于95%,反应72 h内催化剂性能稳定,较优的丙烷反应空速为1 500/h。

Pt-Sn/Al2O3catalyst was prepared by the high pressure impregnation method,mass fraction of Pt was0.25%.The performance of catalyst was evaluated by dehydrogenation of propane to propylene.The effect of the crystal of alumina,preparing methods,the mount of Sn addition and airspeed on the performance of the catalyst was investigated.The results showed that the samples prepared fromθAl2O3were more active thanγAl2O3andαAl2O3showed lower activity.Compared with conventional impregnation method,the activity of catalyst prepared high pressure impregnation method is higher.The addition of Sn has a great influence on the conversion,selectivity and stability of catalyst.Dispersion is positively correlated with catalyst activity.When the molar ratio of Pt to Sn is1∶2.5,the catalyst has the highest activity and dispersion,conversion rate is35.6%and selectivity is more than95%,the activity of the catalyst is stable within72h,the optimal propane reaction airspeed is1500/h.