负载型铁基高温变换催化剂的制备和性能研究

分别以镁铝尖晶石和活性炭作为载体制备了负载型铁基高温变换催化剂，通过XRD、TEM和活性评价测试，考察了催化剂的结构和催化反应性能。以镁铝尖晶石负载γ-Fe₂O₃制得的催化剂，其催化活性明显高于负载α-Fe₂O₃催化剂，当催化剂组成为：Fe₂O₃ 26%，K2O 2%，MgO 0.05%，Cr₂O₃ 0.7%时，400℃下CO转化率为92%，350℃为84%（汽/气=1， 空速=2000 h^-1）；经氧化处理的活性炭作为催化剂载体时，低铬条件下也具有较好的催化活性，当负载量为40%时，相同变换反应条件下CO的转化率在400℃和350℃下分别为88%和80%。两种催化剂在低Cr₂O₃含量时都保持了与传统铁铬系变换催化剂(B117型)相当的催化活性，对于改善环境具有很大意义。

Preparation and properties of iron-based high-temperature water-gas shift catalysts

Iron-based high temperature water gas shift (WGS) catalysts supported on MgAl₂O₄ spinel and activated carbon were prepared, respectively. Structures of the catalysts were characterized by means of XRD and TEM techniques and the activity of the catalysts studied. Results showed that these two sorts of catalysts with lower loading of Cr₂O₃ have almost the same catalytic activitiy as traditional Fe-Cr WGS catalysts. The activity of γ-Fe₂O₃ supported on MgAl₂O₄ spinel is higher than that of α-Fe₂O₃ supported on MgAl2O4 spinel. The optimal composition is 26% Fe₂O₃, 2% K₂O, 0.05% MgO and 0.7% Cr₂O₃ for maximum WGS activity. Under GHSV 2000 h^-1 and steam/gas ratio 1, CO conversion of 92% (at 400℃) and 84% (at 350℃) were obtained. Catalysts supported on oxidized activated carbon with 4% Cr₂O₃ also have excellent activity, with CO conversion of 88% at 400℃ and 80% at 350℃.