沉淀铁催化剂在F-T合成反应过程中的物相变化  

Phase Change of Precipitated Iron Catalyst during Reaction Process of Fischer-Tropsch Synthesis

作　　者：张荣乐[1] 白亮[1] 杨勇[1] 相宏伟[1] 李永旺[1] 周敬来[1] 

机构地区：[1]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001

出　　处：《催化学报》2004年第5期409-412,共4页

基　　金：国家科技部 863项目 (2 0 0 1AA5 2 3 0 10 );中国科学院知识创新重大项目 (KGCX1 SW 0 2 ) .

摘　　要：采用元素分析、X射线衍射和穆斯堡尔谱等手段研究了喷雾干燥沉淀Fe Cu K/SiO2 催化剂在F T合成反应过程中的物相变化 .结果表明 ,新鲜催化剂样品主要由α Fe2 O3 组成 ,且 81 1%的α Fe2 O3 粒径小于 13 5nm .随着反应时间的延长 ,催化剂表面碳沉积物的含量逐渐增多 ,不饱和度逐渐增大 ;χ Fe5C2 的含量逐渐增多 ,Fe3 O4的含量逐渐减少并趋于稳定 .超顺磁Fe3 + 的含量呈先增加后减少的变化趋势 .由于碳沉积物是由CO生成的 ,而 χ Fe5C2 是由α Fe2 O3 经Fe3 O4生成的 ,故催化剂表面碳沉积物的生成先于 χ Fe5C2 的生成 .The phase composition of spray dry precipitated Fe-Cu-K/SiO 2 catalyst for F-T synthesis was characterized by element analysis, X-ray diffraction and Mssbauer spectroscopy. The content of insoluble carbonaceous deposit and the C/H mole ratio on the catalyst surface increased with the time on stream. α-Fe 2O 3 was found in the fresh catalyst, and α-Fe 2O 3, Fe 3O 4 and χ-Fe 5C 2 were found in the catalyst samples after reaction for 19 and 451 h, respectively. With the increase of time on stream, the content of χ-Fe 5C 2 gradually increased, and the amount of Fe 3O 4 decreased nearly to stability; the content of Fe 3+ in a superparamagnetic state increased first, and then decreased. The formation of insoluble carbonaceous deposit was prior to that of χ-Fe 5C 2 owing to carbonaceous deposit from CO and χ-Fe 5C 2 from α-Fe 2O 3 via Fe 3O 4.

关 键 词：费托合成 铁 铜 钾 二氧化硅 碳沉积物 碳化铁 

分 类 号：O643[理学—物理化学]