Fischer–Tropsch synthesis in milli-structured fixed-bed reactors: Experimental study and scale-up considerations

The low-temperature Fischer–Tropsch synthesis (FTS) over a CoRe/γ-Al2O3 catalyst in milli-structured fixed-bed reactors was studied experimentally and theoretically. Kinetic and pressure drop measurements were conducted in a capillary with a catalyst bed length of 1 m. Ergun constants for calculation of the pressure drop were determined by measurements in the absence of reaction. Kinetic constants for the assumed first-order kinetics were obtained with the aid of a reactor model taking into account the volume contraction during reaction as well as the pressure drop. With the same model, values for the liquid holdup in the reactor were estimated. Finally, simulations for a scale-up of the reactor were conducted. It could be shown that effective heat removal is possible even for reaction channel widths of 1.5 mm and 3 mm. Catalyst particle sizes of 100 μm, 200 μm and 350 μm allow for high effectiveness factors at acceptable pressure drops. High catalyst and reactor volume specific productivities can be obtained resulting in compact and efficient reactors. In conclusion, milli-structured fixed-bed reactors appear to be an interesting concept especially for small-scale FTS units.