Coking of Iron Sulfide Catalysts During Hydroliquefaction of Coal

Abstract Catalysis of coal hydroliquefaction (HL) was studied over highly dispersed and non porous iron sulfide catalysts (non stoichiometric pyrrhotites). The active interface between the bulk catalyst and the reactional mixture was built during liquefaction and a coke layer was deposited on the Fe 1-x S surface. During HL the first role of this coke was to prevent the sintering of the catalyst particles. Two kinds of coke were identified according to the mode of sulfidation and introduction of the catalyst into the autoclave. The catalytic roles of the interface were discussed in terms of solvent rehydrogenation, pool of active hydrogen (spillover effect) and stabilization of radicals.