Fe-Co/SiO_2双金属催化剂上费托合成反应的研究

Catalytic Performance of Fe-Co/SiO_2 Bimetallic Catalyst in Fischer-Tropsch Synthesis

采用浸渍法制备Fe-Co／SiO2双金属催化剂，考察了不同反应温度、压力、空速下催化剂的反应性能。实验结果表明，在230～300℃的温度范围内，随反应温度升高，催化剂活性提高，甲烷选择性上升，水煤气变换程度逐渐增大，而C2～C4烯烃／烷烃比和C5^＋选择性下降；压力增加有利于反应活性的提高和重质烃的合成，当压力大于1．5MPa，CO的转化率、水煤气变换程度、C5^＋选择性C2～C4烯烃僬烃比变化不太明显；随空速增加，CO转化率下降，产物中低碳烃含量增加，说明高空速不利于重质烃的生成。XRD结果表明反应前催化剂主要成分为CO3O4和Fe2O3，反应后则为FeCo合金。

Silica supported iron-cobalt catalyst was prepared by incipient wetness impregnation. The effects of reaction temperature, system total pressure, and space velocity on catalytic performance were studied. The results showed that, in the temperature range of 230℃ to 300℃, the increase of reaction temperature enhanced CO conversion, selectivity of methane and WGS（water gas shift） extent, but the mass ratio of olefin to paraffin of C2（C4（O/P） and selectivity of C5^＋ hydrocarbons decrease with the increase of reaction temperature. The increase of total pressure enhanced the activity of the catalyst and favored heavy hydrocarbons producing, but when＇ the pressure was over 1.5MPa, the CO conversion, WGS extent, selectivity of C5^ ＋ hydrocarbons and O/ P didn＇t Change markedly. The increase of GHSV decreased CO conversion and select!yity of C5^＋ hydrocarbons. High space Velocity inhibited producing heavy hydrocarbon and was favorable to the formation of lower hydrocarbons. XRD revealed that the spinel phases of the fresh Fe-Co/SiO2 catalyst are Co3O4 and Fe2O3 crystallites, and Fe-Co alloy phase is present in the system after test.