Evolution of highly dispersed catalysts during hydroliquefaction of coal

Abstract

Two iron oxides aerosols with low particle sizes ( < 80 nm) were used as catalyst precursors in hydroliquefaction of coal (Freyming, France). Their sulfidation was carried out in situ by addition of elemental sulfur. As shown by X-ray diffraction patterns and TEM/STEM-X-ray microanalysis (EDS), the resulting non-stoichiometric pyrrhotites were highly sensitive to sintering in the absence of coal. The phenomenon was strongly inhibited in the presence of coal probably due to textural promotor effects of the heavy organic residues deposited at the surface of the catalyst during the reaction.