Fischer–Tropsch principles of co-hydrogenation on iron catalysts
Fischer–Tropsch principles of co-hydrogenation on iron catalysts
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DOI：
10.1007/s11244-005-2883-8
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发表时间：
2005-03
影响因子：
3.6
通讯作者：
H. Schulz;T. Riedel;G. Schaub
中科院分区：
文献类型：
--
作者：
H. Schulz;T. Riedel;G. Schaub
使用碱化沉淀铁催化剂，在 250°C、1 MPa 下，使用 H2/CO2 摩尔比为 3 的特殊合成气，研究了产品组成的时间变化以及催化剂组成和结构的变化。据观察，合成的稳态在具有单独动力学机制的几个事件期间在自组织过程中发展。 “真正的费托催化剂”显然是在α-铁完全消耗并形成碳化铁（Fe5C2）的反应条件下“构建”的。磁铁矿相部分消失，并形成新的“未知”（可能是 FeOx）相。从链增长和分支概率的数据得出结论，在自组织过程中，仅站点数量增加，但其性质保持不变。这些地点似乎受到强烈的空间限制。 与钴催化剂上的 FT 合成相比，铁催化剂上的 FT 位点非常稳定，不会随反应条件的变化而变化。这些站点显示出动态行为。
The temporal changes of product composition together with changes of the catalyst in composition and structure have been investigated for Fischer–Tropsch synthesis with an alkalized precipitated iron catalyst at 250°C, 1 MPa, using a special synthesis gas with a molar H2/CO2-ratio of three. It was observed that the steady state of synthesis developed in processes of self-organization during several episodes with individual kinetic regimes. The“true FT catalyst” apparently was “constructed” at reaction conditions under complete consumption ofα-iron and formation of iron carbide (Fe5C2). The magnetite phase disappeared partially and a new “unknown” (probably FeOx) phase was formed. It has been concluded from the data of chain growth and branching probability that during self-organization only the number of sites increased but their nature remained unchanged. Strong spatial constraints appear to apply at the sites. On iron catalysts, the FT sites are very stable, invariant against changes in reaction conditions, in contrast to FT synthesis on cobalt. There the sites show a dynamic behavior.