Effect of Reduction Parameters on the Structure of Fe-Mn Catalyst for Fischer-Tropsch Synthesis

The effects of reductants and reduction pressure on the textural properties and phase composition of the spherical Fe-Mn Fischer-Tropsch synthesis catalyst were investigated in a slurry reactor. It was found that the BET surface area of the H_2-reduced catalyst is the biggest. The BET surface area of the catalyst monotonically decreased with the decrease of H_2/CO ratio when syngas or CO was used as reductant, which can be due to the carbon deposition. The Fe_xC content in the reduced catalysts increased with the decrease of H_2/CO ratio. The BET surface area of catalysts decreased with the increase of reduction pressure, while the Fe_xC content firstly increased and then decreased with the increase of the reduction pressure for syngas reducing. This trend might be ascribed to the high H_2O/H_2 ratio in the system at high reduction pressure which re-oxidized the iron carbide(s) formed during the reduction.