Particularities of low-temperature WGSR over ceramometal and oxide catalysts: Effect of catalyst particle size

Two types of the low temperature WGS catalysts were compared: oxide Cu-Zn-Al catalyst prepared through coprecipitation procedure and ceramometal CuAlO/CuA catalyst prepared from powdered CuAl alloy. The catalysts were characterized by XRD, SEM with EDX, adsorption-desorption isotherms. Activity was measured at a pressure of 1 bar in the mixture of CO:Н₂О:Н₂ = 8:42:50 at a steam/gas ratio of 0.6–0.7. The catalysts were used as a small (0.14–0.25 mm)and large (3.2 × 3.2 × 5 mm)fraction. It was found that oxide catalyst possesses of a developed mesopore structure with specific surface area 122 m²/g while ceramometal catalyst has a developed macropore structure with size up to ten microns and specific surface area 15.7 m²/g. As a result, large fraction (granules)of ceramometal catalyst has twofold higher effectiveness factor due to higher internal diffusion.