Abstract:
A serial of Fischer-Tropsch synthesis catalysts (Fe-Cu-K-SiO2) was prepared by the co-precipitation method with varied pH of 6~8. The properties of the catalysts, i.e. crystal phase, particle size, pore structure, reducibility and carburization, were studied by XRD, N2 adsorption, H2-TPR, and Mssbauer spectroscopy. The catalysts were evaluated for Fischer-Tropsch synthesis under typical industrial conditions. The results indicate that the increase of pH values increases the particle size and decreases the surface area, which inhibit the reduction and carburization of the catalysts. As a result, a lower CO conversion and a lower selectivity of CH4 but a higher selectivity of CO2 and C5+ products were obtained in Fischer-Tropsch synthesis. By correlating the Mssbauer characterization with catalytic results, the CO conversion is revealed to be dependent on the Fe5C2 phase while CO2 selectivity is related to Fe3O4 phase over the catalyst.