费-托合成Fe_(1-x)O基熔铁催化剂的研究

Study on Fe_ (1-x)O-Based Fused Iron Catalyst forFischer-Tropsch Synthesis

采用高温熔融法制备了用于费 托合成的Fe1 xO基熔铁催化剂 ,考察了其在n(H2 ) /n(CO) =2 ,温度 5 73K ,压力 1 4MPa和空速为 12 6 0 0h-1下的催化性能 .结果表明 ,与Fe3 O4基熔铁催化剂相比 ,Fe1 xO基熔铁催化剂具有较高的催化F T合成反应的活性、较低的WGS反应选择性和较强的加氢能力 .XRD结果表明 ,经F T反应后的熔铁催化剂存在Fe5C2 和Fe3 O4两种物相 ,但Fe1 xO基熔铁催化剂中Fe5C2 的晶粒尺寸小于Fe3 O4基熔铁催化剂中Fe5C2 的晶粒尺寸 .

The Fe 1-xO-based fused iron catalyst for Fischer-Tropsch (F-T) synthesis was prepared by fusion method in an electric furnace at about 1?800 K, and the n(Fe 2+)/ n(Fe 3+) ratio was determined by EDTA volumetric analysis. The catalytic performance of the fused iron catalyst for F-T synthesis was investigated under conditions of n(H 2)/ n(CO)=2, T=573 K, p=1.4 MPa and GHSV= 12?600 h -1 using a fixed-bed reactor. The results indicated that the Fe 1-xO-based fused iron catalyst had higher F-T activity and lower selectivity for the water gas shift (WGS) reaction than the Fe 3O 4-based fused iron catalyst. The space-time yield of C 5+ over the Fe 1-xO-based and Fe 3O 4-based catalyst was 0.188 and 0.115 g/(g·h), respectively. The hydrocarbon distribution in products implied that the hydrogenation ability of Fe 1-xO-based catalyst was higher than that of Fe 3O 4-based catalyst. Meanwhile, the Fe 1-xO-based fused iron catalyst was found more resistant to disintegration than the Fe 3O 4-based catalyst. XRD result showed that the bulk phase of fresh Fe 3O 4-based catalyst consisted of Fe 3O 4 and FeO, while that of fresh Fe 1-xO-based catalyst consisted of wustite ( Fe 1-xO) only. There existed two kinds of active phases, Fe 5C 2 and Fe 3O 4, on the used fused iron catalyst, and the average crystal size of Fe 5C 2 on the used Fe 1-xO-based catalyst was smaller than that on the used Fe 3O 4-based catalyst.