【摘要】 考察了助催化剂对Fe1-xO基合成熔铁催化剂反应性能的影响,并通过XRD和TPD对催化剂进行表征。结果表明,MnO可以使产物中甲烷选择性降低,低碳烯烃的选择性增加,(CO+H2)转化率下降。稀土氧化物M2O3(M=La、Nd、Pu等)的加入,产物中甲烷的选择性降低,低碳烯烃的选择性增加,C5+选择性增加。对于熔铁催化剂,较少量M2O3(质量分数为0.5%~1.0%)的加入可以使甲烷选择性由21.1%降到14.84%,低碳烯烃收率由31.20 g.m-3升高到40.91 g.m-3,C5+收率由45.52 g.m-3升高到59.61 g.m-3,但是较多量M2O3(质量分数为1.5%)的加入,(CO+H2)转化率大幅下降,(CO+H2)转化率仅为30.29%。XRD结果表明,加入MnO,Mn2+部分取代了较大离子半径的Fe2+的位置,晶胞参数变大;M2O3的加入,形成了新的晶相。TPD结果表明,低温脱附峰的面积在添加MnO或M2O3后明显减少,催化剂表面活性中心数目减少。更多还原

【Abstract】 The effects of MnO and M₂O₃ promoters on Fischer-Tropsch synthesis behaviors over(Fe_1-xO-)Based fused iron catalyst was investigated by means of CO hydrogenation,XRD and CO-TPD techniques.The results showed that selectivity to methane decreased,CO+H₂ conversion decreased,and selectivity to light olefins increased with the addition of MnO.Selectivity to methane decreased from 21.18% to 18.84%, light olefins yield remarkably increased from 31.20 g·m^-3 to 40.91 g·m^-3,and C⁺₅ yield increased from 45.52 g·m^-3 to 59.61 g·m^-3 with the addition of 0.5%-1.0wt% rare earth oxide of M₂O₃（M=La,Nd,Pu,etc）. However,CO+H₂ conversion declined to 30.29%with the addition of（1.5wt%）M₂O₃.XRD results indicated that,with the addition of MnO,Mn²⁺ replaced Fe²⁺ in the lattice of Fe_1-xO,and lattice parameter of Fe_1-xO increased.New crystalline phase formed with the addition of M₂O₃.CO-TPD results indicated that the area of desorption peak observably decreased with the addition of M₂O₃ or MnO.更多还原