The results of a two-stage conversion of brown coal (gross-formula CH0.96N0.01S0.002O0.31) in supercritical water (SCW) under isobaric conditions (30 MPa) in the vertical tubular reactor of an original configuration are presented. The first stage provides for a continuous supply of coal-water slurry (CWS) into the reactor and discharging of the products with SCW into the demountable samplers. The CWS composition was as follows (weight portions): coal-100, water-125, and starch-2.25. It was found out that when increasing the temperature of coal particles up to 600 degrees C during their falling down along the reactor aids, the yields of volatile and liquid products were 25.4 and 27.5%, respectively, relative to the weight of organic matter supplied into the reactor. At the second stage of conversion, the SCW/O-2 fluid was pumped through a layer of coal particles accumulated at the reactor bottom during the first stage. It was shown that as a result of heat emission during partial oxidation of coal residue, the autothermal conditions for conversion were realized. The yields of volatile combustible and liquid products at conversion in the SCW/O-2 fluid were 25.1 and 3.4 wt.%, respectively. The increment of hydrogen in the conversion products caused by water decomposition was equal to 20% relative to the weight of hydrogen in initial coal. (C) 2015 Elsevier B.V. All rights reserved.