Effects of Catalytic Activity and Solvent Composition on Two-Stage Coal Liquefaction

Abstract

Catalytic activities of NiMo supported on hollow carbon black (Ketjen Black), a commercial NiMo/alumina, and a synthetic pyrite were examined in the single- and two-stage liquefaction of Wyoming subbituminous and Yallourn brown coals with tetralin or 1-methylnaphthalene. The two-stage liquefaction consisting of lower temperatures (<400 °C) in the first stage and high temperatures around 450 °C in the second stage was very effective for the conversion of asphaltene and preasphaltene components into oil fractions with the suppression of gas formation, providing the oil yield above 70 wt %, which was much larger than that obtained by the single stage of 450 °C−60 min. The NiMo/KB catalyst exhibited a much higher activity for the production of the lighter oil fraction in the two-stage liquefaction than a commercial NiMo/Al2O3 and a synthetic pyrite, especially when 1-metylnaphthalene of nondonor solvent was used, reflecting the higher activity of NiMo/KB catalyst for the hydrogenation of solvent as well as th...