抗硫中毒Pt/CeO_2/Al_2O_3催化剂 Ⅱ.汽油自热重整反应性能和催化剂表征

以硫含量为500 μg/g 的零售汽油为原料,考察了水与碳的摩尔比、O_2与碳的摩尔比、反应温度和汽油重时空速对 Pt/CeO_2/Al_2O_3催化剂自热重整性能的影响,得到了优化的反应条件,并在优化条件下考察了 Pt/CeO_2Al_2O_3催化剂自热重整高含硫汽油的稳定性。实验结果表明,在水与碳的摩尔比为5、O_2与碳的摩尔比为0.35、800℃、汽油重时空速0.9 h~(-1)的优化条件下,零售汽油转化率可达100%,产物中 H_2的摩尔分数为69.0%,CH_4的摩尔分数为1.0%,且催化剂的稳定性很好。氢-程序升温还原表征结果显示,被还原的 Pt/CeO_2/Al_2O_3催化剂中 CeO_2表面晶格氧在 O_2中比在水蒸气中容易恢复,因此,自热重整反应中积碳的消除和有机硫的转化能快速进行,从而使催化剂具有良好的稳定性和抗硫中毒性。

Sulfur-Tolerant Pt/CeO2/Al2O3 Catalyst Ⅱ.Performance of Autothermal Reforming of Gasoline and Characterization of Catalyst

Effects of reaction parameters,namely n(H_2O):n(C)(C in gasoline),n(O_2):n(C), reaction temperature and WHSV of gasoline on performance of Pt/CeO_2/Al_2O_3 catalyst in autothermal reforming(ATR)of retail gasoline with 500μg/g sulfur were investigated.Catalyst stability in ATR of gasoline was tested in presence of sulfur under optimal reaction conditions.Gasoline conversion of 100% was obtained with H_2 mole fraction of 69.0% and CH_4 mole fraction of 1.0% in the gas product under the conditions:800℃,WHSV 0.9h~(-1),n(H_2O):n(C)5 and n(O_2):n(C)0.35.The stability of the Pt/CeO_2/Al_2O_3 catalyst in ATR process showed dramatic improvement comparing with steam reforming.The H_2-TPR results indicated that Ce~(3+)in reduced Pt/CeO_2/Al_2O_3 catalyst can retrieve to highly active state of CeO_2 by reacting with O_2 rather than H_2O.In other words,the catalyst can get abundant highly active lattice oxygen from O_2 to meet the requirement of coke removal and organo-sulfur conversion thereby leads to good stability and high sulfur resistance.