Influence of calcination on physico-chemical properties and Ficher-Tropsch activity of titanosilicate supported cobalt catalysts with different pore sizes

摘要

Titanosilicate supports of different pore sizes were synthesized by a surfactant-free templating method. Cobalt was loaded by incipient wetness impregnation on the synthesized supports and commercial gamma-Al2O3. The Fischer-Tropsch activities of the catalysts were studied with and without prior calcination in a fixed bed reactor at 220 degrees C, 1.83 MPa and 2000 mL(syngas)/mL(catalyst)/h after in situ reduction. XANES analysis of the catalysts revealed that after reduction, a greater fraction of the loaded cobalt had been reduced in the calcined catalyst (74 %) compared to the uncalcined catalyst (58 %). Activity studies revealed that the CO conversion and C5+ selectivities of the catalysts with medium pore titanosilicate supports was higher (80 % conversion, 81-85 % selectivity) than the CO conversion by Co/gamma-Al2O3 (77 % conversion, 76 % selectivity). Calcination in air increased the liquid product selectivity of all the catalysts towards the diesel fraction from 21-24 % to 25-32 %.