Illinois No. 6 bituminous coal with small concentrations of coal-derived solvent was subjected to hydroliquefaction in batch reactors to which substantial amounts of water were sometimes added. The reactions were catalyzed by 0.1% molybdenum on mf coal, added as a water-soluble salt. It was shown previously that a substantial water partial pressure, at fixed hydrogen partial pressure, increases coal conversion in uncatalyzed systems. The present work investigated the effect of added water in catalyzed systems. Considerations of process economics led to the performance of series of reactions at constant total pressure while the partial pressures of water and hydrogen were varied. For catalyzed systems containing solvent, at fixed total pressure, highest conversions are obtained without added water. Conversion to THF solubles is independent of the solvent-to-coal (S/C) ratio to very low values, S/C ^0.25, due to the catalyst. At 427 °C and 1500 psig hydrogen partial pressure, THF and benzene conversions exceeding 90% and 85%, respectively, were achieved. It is concluded that reaction systems with catalyst deposited from solution on the coal particles are highly reactive. Added water is preferentially excluded from the reactor, but water retains a role as a solvent for the catalyst and potentially as a transport medium for coal feed in continuous processing.

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