Direct liquefaction of vitrinite concentrates obtained by column flotation

In this paper, direct liquefaction of vitrinite maceral concentrates was studied. Coals from Cerrejon and Jagua collieries (Colombia, South America) were used. Vitrinite concentrates were obtained by column flotation at pH 7, air velocity of 1.4 cm/s and frother concentration of 4 ml of frother/kg of coal. Digestion runs were made at 380, 400 and 420 °C and ratios tetraline/coal (S/C) of 2/1, 2.5/1 and 3/1. Liquefaction time was 30 min. For all runs, tetraline was the hydrogen donor solvent. Feed and vitrinite concentrates were liquefied in order to compare their conversion, product distribution and oils selectivity. It was observed that, in general, conversion rates obtained from vitrinite concentrates were higher than those obtained from feed coal. The results showed that conversion tend to increase with temperature as well as the S/C ratio. Product distribution showed that both oils and gas fractions tend to increase with temperature and S/C ratio, whereas residues have a contrary behaviour.