Coal hydroliquefaction using MoCl₃- and NiCl₂-containing salts as catalysts: difference in catalysis between solid and molten catalysts

Both MoCl₃- and NiCl₂-LiCl-NaCl-KCl quaternary solid salts and both MoCl₃- and NiCl₂-LiCl-KCl ternarly molten salts were examined as catalysts for hydroliquefaction of subbituminous Wandoan coal at 400 °C for 1 h in a batch reactor with an initial H₂ pressure of 9.8 M Pa. Conversions (to pyridine solubles) and yields of hexane solubles (HS) ranged from 80 to 92 wt% and from 55 to 65 wt%, respectively. The results suggested that both solid and molten catalysts are highly effective for hydrocracking of coal, with the latter being superior in terms of conversion and HS yield. H₂ consumption of the reaction suggested that the hydrogenating ability of the catalysts decreases in the following order: NiCl₂ (molten) > MoCl₃ (molten) > MoCl₃ (solid) > NiCl₂ (solid). Cracking ability of these catalysts decreases in the order: MoCl₃ (molten) > MoCl₃ (solid) > NiCl₂ (molten) > NiCl₂ (solid). It was tentatively concluded that the molten catalysts have higher hydrogenating and cracking abilities for coal hydroliquefaction than the corresponding solid ones.