Research paperComparing a cobalt-based catalyst with iron-based catalysts for the Fischer-Tropsch XTL-process operating at high conversion

- Activity of Co-based catalysts are less dependent on CO-conversion compared to Fe-based catalysts.
- Low methane selectivity (CO2-free basis) can be obtained with Fe-based catalysts.
- Higher methane selectivity with Co-based catalysts compared to Fe-based catalysts is off-set by a lower C2-C4-selectivity.
- C5+-selectivity (CO2-free basis) obtained over Co-based catalysts comparable to that obtained over Fe-based catalysts.

The XTL-process is a capital-intensive process. Novel process configurations need to be explored to increase the economic viability of this process. This is typically performed using the known dependencies of the catalyst as a function of the targeted process conditions. However, new process conditions may require catalysts with different characteristics compared to those currently utilised. Here, a set of cobalt- and iron-based Fischer-Tropsch catalysts are evaluated for their suitability in the application of a single-pass XTL-process operating at high conversion of synthesis gas. It is shown that cobalt-based catalysts of a suitable activity may be preferred over iron-based catalysts. The higher selectivity for methane for cobalt-based catalysts is offset by a lower selectivity for C2-C4 resulting in a favourable C5+-selectivity.

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