CoAl2O4/Al2O3载体对钴基费托催化剂反应性能影响的研究

Catalytic properties of CoAl2O4/Al2O3 supported cobalt catalysts for Fischer-Tropsch synthesis

  • 摘要: 通过浸渍和高温焙烧,制得表面附着CoAl2O4微晶颗粒的改性Al2O3载体,并采用等体积浸渍法制备负载型Co基催化剂。结合 N2物理吸附、XRD、H2-TPR、XPS及H2化学吸附等表征手段,研究改性载体及其负载钴基催化剂的织构特征;采用费托合成反应评价其催化性能。结果表明,Al2O3改性后,表面CoAl2O4的存在有效减少了载体与活性组分Co的相互作用,显著提高了催化剂的还原度和催化活性。载体的改性量在20%左右达到最佳值,继续增加,催化剂还原度和活性基本不再升高。载体改性促使催化剂CH4选择性有所降低,C5+选择性略有提高。

     

    Abstract: The γ-Al2O3 modified with CoAl2O4 by the impregnation method was used as support to prepare cobalt catalysts. The physicochemical properties of the prepared catalysts were characterized with BET, XRD, H2-TPR and XPS techniques and H2-chemisorption experiment. The catalytic properties of the prepared catalysts were investigated for Fischer-Tropsch synthesis. It was shown that CoAl2O4 existed on the surface of γ-Al2O3, and thus, effectively weakening the interaction of Co and Al2O3 and resulting in a great increase in the reduction degree and the catalytic activity. The sample with a CoAl2O4 content of 20% shows the highest catalytic activity. It is worth noting that the CoAl2O4 modification decreased the CH4 selectivity but enhanced the C5+ selectivity and catalytic stability.

     

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