2.2. Catalytic tests
2.2.1. Low-pressure testing
The Fischer–Tropsch synthesis was performed at 1 bar and
350 C in a fixed-bed reactor using 0.02 ± 0.005 g of catalyst
(particle size 0.2–0.4 mm) and 0.2 g of SiC (0.2 mm) for bed dilution.
The catalyst was reduced prior to reaction at 350 C with a
mixture of H2 and He (33% H2 v/v, 60 ml min1 total flow) for
2 h. After reduction, the feed flow was switched to a mixture of
H2 and CO (H2/CO = 1 v/v, GHSV = 10500 h1). The reaction was
carried out for 20 h. The CO conversion levels were lower than
1% to ensure differential operation, thus limiting the extent of secondary
reactions. Under these conditions, the products remained
in the gas phase and were analyzed with online gas chromatography
(C1–C16). CO2 was not measured. Product selectivity was calculated
as equivalent of carbon atoms in a product with respect to the
total carbon atoms present in the hydrocarbons produced (%C). The
activities and selectivities reported here were determined after