DIRECT LIQUEFACTION OF COAL USING FERRIC-SULFIDE-BASED, MIXED-METAL CATALYSTS CONTAINING MG OR MO

Direct liquefaction of coal was studied using ferric-sulfide-based mix ed-metal catalysts containing magnesium or molybdenum as the second me tal. The catalysts were mostly impregnated in situ on the coal, althou gh physical mixtures of catalyst and coal were also used in some runs for comparison. The liquefaction was performed at 350-440 degrees C un der a hydrogen pressure of 6.9 MPa (cold). Tetralin and phenanthrene w ere used as solvents. The catalytic effects became more evident with p henanthrene as solvent. The activities of impregnated catalysts were 5 -8% higher than those of the physical mixtures of catalyst and coal. T he addition of magnesium was found to be not particularly beneficial t o the activity and selectivity of the catalyst. The addition of molybd enum increased the catalyst activity by up to 8 wt%, resulting in conv ersions of >90 wt% at 400 degrees C. The yield of the oil fraction als o increased considerably in the presence of molybdenum, especially at 400 and 440 degrees C. The activity of the catalyst decreased by simil ar to 5% when it was exposed to air. Copyright (C) 1996 Elsevier Scien ce Ltd.