摘要
研究了以活性炭 (AC)作为载体制备的铁基催化剂 ,通过对不同铁盐、活性炭和助剂的筛选 ,研制出对合成气转化为低碳烯烃具有高活性和高选择性的催化剂 .对反应前及反应过程中催化剂体相结构的XRD测试结果表明 ,Fe Cu K/AC催化剂在反应前主要由α Fe,Fe3 O4和Cu0 组成 ,经合成气反应后主要由α Fe ,Fe5C2 ,Fe7C3 ,Cu0 和K2 O组成 .Fe Mn K/AC催化剂的晶体结构主要以Fe嵌入MnO中形成的 (Fe,Mn)O结构存在 .实验中得出的α Fe ,FexCy 及 (Fe ,Mn)O与激光热解法制备的催化剂的的晶体结构相似 .对催化剂的制备方法进行了筛选 ,考察了不同助剂Cu ,Mn ,Si和K等元素对催化剂性能的影响 .结果表明 ,以草酸铁为铁源 ,椰壳炭为载体制备的Fe Mn K/AC催化剂的催化效果最佳 ,在空速 6 0 0h-1,压力 1 5MPa和温度 32 0℃条件下 ,CO转化率可达 97 4 % ,C=2 ～C=4选择性可达 6 8 0 % .
The synthesis of light olefins via carbon monoxide hydrogenation is effective means to resolve the increasing shortage of petroleum resources. We have previously reported the Fe 3C ultrafine particle catalyst prepared by laser pyrolysis method, while its industrialization is difficulty owing to its expensive cost. This paper reports a series iron based catalysts supported on activated char (AC) that were prepared from different iron sources (ferric citrate, ferric oxalate and ferric nitrate), different activated char (activated cocoanut char GH101 and activated nut char GH81) and different promoters. Carbon monoxide hydrogenation reaction was performed over the Fe/AC catalysts. It was found that the Fe/AC catalysts exhibit rather higher activity and selectivity for light olefins. XRD characterization shows that the bulk phase of fresh Fe Cu K/AC catalyst consists of α Fe, Fe 3O 4 and Cu 0. After the reaction of Fischer Tropsch synthesis, the bulk phase structure of the catalyst converted to α Fe, Fe 5C 2, Fe 7C 3, Cu 0 and K 2O. The bulk phase structure of Fe Mn K/AC catalyst is mainly (Fe,Mn)O mixed crystal. The α Fe, Fe x C y and (Fe,Mn)O from our experiment are similar to the active phases of the Fe/C catalyst prepared by laser pyrolysis. The performance of catalyst was characterized, the result shows that the Fe/AC catalysts originally prepared with ferric oxalate as iron source, with GH101 as supporter, and with Cu, Mn, Si and K as promoters generally exhibit high activity. The influence of different potassium salts on the Fe/AC catalysts was investigated. The result indicates that under the conditions of SV=600 h -1 , p =1 5 MPa and θ =320 ℃, the Fe Mn K 2CO 3/AC catalyst is the most effective catalyst with CO conversion up to 97 4% and C = 2～C = 4 selectivity up to 68 0%.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2003年第4期259-264,共6页
