Formation and Carbon Deposition on Iron Catalysts

Carbide Formation and Carbon Deposition on Iron Catalysts 

The fomation of carbon on iron and iron-copper catalysts by the reaction 2C0 = C02+C has been studied by several investigators (70-73). The most significant result of this work (in so far as the Fischer-Tropsch synthesis is concerned) is the fact that neither an iron-free nor a copper-free carbon deposit was obtained. The data show that cai-bon is deposited in the crystal lattice of the catalyst and the inability to obtain a copper-free carbon deposit from tests with an iron-copper catalyst shows that iron carbonyl formation will not explain the results. It is very probable that carbon is formed from carbon monoxide b3 way of iron carbide as an intermediate. Carbidic carbon diffuses rapidly throughout the crystal lattice and subsequently decomposes to yield elemental carbon, thus disrupting the lattice structure. 

Pichler and Merkel (74) at the Kaiser Wilhelm Institut fiir Kohlen- 

If one assumes that elemental carbon formation occurs by way of some form of iron carbide as an intermediate, the fact that increasing the Hj CO ratio in the synthesis gas reduces the rate of carbon formation may be explained in either of two ways  

Kinetics and Reaction Mechanisms in the Fischeh-Thopsch Synthesis 

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V. Carbide Formation and Carbon Deposition on Iron Catalysts... 

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