1990 年 69 巻 6 号 p. 440-445
The recycle solvents from two stage liquefaction of Yallourn and Taiheiyo coals were analyzed to verify the effect of solvent quality on the promotion of coal conversion observed in the experiments using red mud and NiMo/Al2O3 at the first stage.
The start-up solvent, tetralin decreased in amount progressively with cycle number, and coal-derived components including nondistillable bottom increased gradually in the recycle solvent. GC analyses revealed that hydroaromatics accumulated over successive passes as well as polycondensed aromatics, such as phenanthrene, fluoranthene and pyrene.
Accordingly, the changes in composition seem to enhance hydrogen donor ability for solvents in the last several passes, which accounts for the restriction of n-paraffin accumulation into the recycle solvent produced from Taiheiyo coal.
Moreover, it was shown under the experimental conditions that there was no distinct difference in the properties of bottoms from Yallourn and Taiheiyo coals. This is due to the promotion of hydrogenation and deoxygenation reaction in addition to the improvement of solvent quality.