| Direct liquefaction properties of coal samples from Heishan, Xinjiang, were studied at lower pressure. First of all, effect of these four factors of initial pressure, reaction time, ratio of solvent to coal, and gas phase, and the three interactions between every couple of them on the coal liquefaction performance was investigated by means of orthogonal design method. Results indicated that:oil yield reached to 52.06%, and conversion 76.51% as conditions of temperature being 430℃,initial hydrogen pressure 6MPa, reaction time 60 minutes, reaction atemsphere pure hydrogen, and ratio of solvent to coal 2.0; in the matter of influence on oil yield, for the four factors S:C and gas phase have high significance affection, initial pressure has small, and reaction time has no when over 45 min, and the three interactions of between every couple of them may be neglected. Secondly, catalytic mechanism of iron-based catalyst at above conditions was studied. Results had showed that oil yield and conversion were 51.73% and 78.32% as amount of Fe was 2.2%(Coaldaf)and ratio of S to Fe was 1.8, which XRD analysis showed that a lot of Fe1-xS produced at 200℃,and the mixed crystal or transformation crystal phenomena did good for the coal liquefaction at 400℃and hydrogen initial pressure 6MPa. Thirdly, the effect of two-stage reaction was superior to that of single-stage reaction. Fourthly, the appropriate rotating speed in the reactor was about 300 R.P.M. Fifthly, oil yield and conversion of the coal sample in the phase of syngas were examined, and gas products analyzed by GC. Finally, performance of liquefacted residues at different ratios of solvent to coal was analyzed by TG, FTIR and Ultimate Analysis.
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