The conditions for complete conversion of Victorian brown coal were investigated with an iron-sulfur catalyst in a continuous reactor system consisting of three stirred tank reactors in series. The coal was found to be completely converted into distillate (b.p. < 420 degrees C) when the gas flow rate (GFR) through the reactors was increased and the slurry-feed rate was reduced at a temperature of 450 degrees C and a pressure of 18.6 MPa. An analysis of the composition of the liquid in the reactors under liquefaction conditions confirmed that the increase in GFR markedly enhanced the stripping of the solvent fraction in the feed slurry and the lighter fraction derived from the coal, resulting in marked increases in the actual residence time (theta(RT)) Of the liquid consisting of the concentrated catalyst and heavy fraction. The stripping effect markedly enhanced liquefaction reactions, thus providing a higher distillate yield. However, the GFR effect was gradually saturated as the liquid remaining in the reactors (reactor liquid) became heavier with the increase in the GFR. The extension of nominal residence time (defined by the ratio of slurry-feed rate to reactor volume, theta(NT)) from reduction of the slurry feed rate was found to be effective in extending the GFR effects under a high GFR condition, resulting in the complete conversion of the coal. In addition, the stripping of the solvent by the increased GFR was also found to be more enhanced at 18.6 MPa than that at 14.7 MPa although its vaporization was suppressed at a higher pressure. This is due to the heavy fraction in the reactor liquid being more hydrogenated over the concentrated catalyst at a higher hydrogen pressure. However, the dependencies of the conversion rate of the heavy fraction on theta(RT) were almost the same for both 14.7 and 18.6 MPa. These results suggested that a complete conversion of the coal could be achieved at 14.7 MPa by using a heavier solvent.