Supercritical phase fischer-tropsch synthesis: Catalyst pore-size effect

✍ Scribed by Li Fan; Kohshiroh Yokota; Kaoru Fujimoto

• Publisher: American Institute of Chemical Engineers
• Year: 1992
• Tongue: English
• Weight: 873 KB
• Volume: 38
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690381014

✦ Synopsis

The Fischer-Tropsch synthesis reaction was conducted in a supercritical fluid medium using a fixed-bed reactor. Tailor-made catalyst supports which had sharp pore diameter distributions were prepared by the pHswing method. The relationships between the catalyst pore structure and the catalytic activity or the product distribution were studied. The influence of the catalyst pore size on the mass transfer of reactants and products was also characterized. The catalyst pore size affected not only catalytic activity but also product selectivity. The diffusion of reactants inside the catalyst pellets in the supercritical fluid media was simulated and the effects of catalyst pore size and catalyst particle size on catalytic performances were consistent with simulation results.

Experimental

Catalyst preparation

Alumina-supported ruthenium catalysts were prepared by impregnating y-alumina with ruthenium chloride from its aqueous solution . The alumina supports with different pore size were prepared from aluminun nitrate and ammonia with the pH swing method (On0 et al., 1982). After precipitation with suitable times of pH swing, the resulting materials were calcined at 600°C for 2 h and were impregnated as mentioned above. Composition of the catalysts was Ru:2 and A1,03:98 by weight. The catalyst precursors were dried overnight at 120°C in ran air oven, and were then calcined at 450°C for 2 h to form a supported metal oxide and to make the ruthenium oxide particles grow on the surface (Fujimoto