The co-liquefaction of lignite coal and used tire was performed in a 250-ml batch reactor, in supercritical
water under a nitrogen atmosphere to investigate the effects of temperature (380-440℃), water/feedstock
ratio (4/1-10/1 (wt./wt.)) and the % used tire content in the feedstock (0-100 wt.%) on the conversion efficiency,
liquid yield and oil composition attained. The maximum conversion and oil yield were 67 and 50%,
respectively, obtained at 400℃ at 1 min, with water/feedstock ratio of 10/1 and 80% used tire content. The
distillation characteristics of the oil products, analyzed by simulated distillation gas chromatography, revealed
that the oil composition depended significantly on the reaction temperature. The co-liquefaction of
coal and used tire yielded a synergistically increased level of oil production. Moreover, the total conversion
level obtained with co-liquefaction alone was almost equal to those obtained in the presence of either Fe2O3
or NiMo as catalysts, under the same conditions. Therefore, supercritical water is a good medium for the
dissolution of the volatile matter from a coal and used tire matrix.