Manufacturing of cobalt catalyst - structural and catalytic properties in Fischer-Tropsch synthesis
Shu, Tong (2009)
2009
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2024090324713
https://urn.fi/URN:NBN:fi:amk-2024090324713
Tiivistelmä
The Fischer-Tropsch synthesis process is focused on the catalytic conversion of synthesis gas (mixture of H2 and CO) over cobalt and iron catalyst into environmental chemical products or fuel components. The purpose of this study was 1) to find out how cobalt catalysts were manufactured and 2) to study the catalytic behavior during the Fischer-Tropsch synthesis process.
A 10 wt% Co/ AhO3 catalyst was prepared by wet impregnation method using a cobalt acetate solution as precursor. A cobalt nitrate aqueous solution was used to manufacture alumina, silica, titania, SBA-15, zeolite and MCM-41 supported cobalt catalysts with a promoter, which included noble metals (i.e. Re, Ru, Pt) and alkali metals (i.e. K, B). The BET surface area, pore volume and average pore diameter were determined by N2-adsorption. Co3O4 crystallite sizes were measured by X-ray diffraction, and temperature-programmed reduction was used to determine the reducibility of the catalyst. The FT activity and selectivity of the catalysts were tested with the H2/CO molar ratio of 2:1.
The type and structure of the support and promoter influenced the catalytic behavior of the cobalt catalyst. The BET surface, dispersion, particle size and reducibility were affected by the support, and the addition of small amounts of noble metal increased the dispersion of cobalt metal and reducibility, thereby affecting activity and selectivity. The deactivation of the cobalt catalyst depended on the concentration of sulfur poisoning and amounts of water.
A 10 wt% Co/ AhO3 catalyst was prepared by wet impregnation method using a cobalt acetate solution as precursor. A cobalt nitrate aqueous solution was used to manufacture alumina, silica, titania, SBA-15, zeolite and MCM-41 supported cobalt catalysts with a promoter, which included noble metals (i.e. Re, Ru, Pt) and alkali metals (i.e. K, B). The BET surface area, pore volume and average pore diameter were determined by N2-adsorption. Co3O4 crystallite sizes were measured by X-ray diffraction, and temperature-programmed reduction was used to determine the reducibility of the catalyst. The FT activity and selectivity of the catalysts were tested with the H2/CO molar ratio of 2:1.
The type and structure of the support and promoter influenced the catalytic behavior of the cobalt catalyst. The BET surface, dispersion, particle size and reducibility were affected by the support, and the addition of small amounts of noble metal increased the dispersion of cobalt metal and reducibility, thereby affecting activity and selectivity. The deactivation of the cobalt catalyst depended on the concentration of sulfur poisoning and amounts of water.