Exfoliated graphite as a heat-conductive frame for a new pelletized Fischer–Tropsch synthesis catalyst

Abstract

The introduction of exfoliated graphite into pelletized Co-based catalysts affects in the most positive way both catalytic and physico-chemical properties. Unlike other carbons, the exfoliated graphite allows combination of extended surface with high thermal conductivity. An open-ended system of slit-type pores is revealed by X-ray tomography. Electron microscopy shows graphitic platelets forming an all-penetrating heat-conductive frame. Element distribution analysis shows that this catalyst cannot be considered as a cobalt-on-carbon catalyst since the graphitic component carries insignificant amount of cobalt and serves as a heat-conductive frame only. Thermal conductivity of a catalyst with graphite frame is 2 times higher than that of its industrial predecessor with Al metal frame and 30 times higher than that of a catalyst without heat-conductive additive. Testing in exothermal Fischer–Tropsch synthesis shows a favorable influence of the graphitic additive, i.e. such catalyst shows productivity of 455 g/kg/h at GHSV of 3000 h−1.