The hydropyrolysis of a Turkish lignite (Tuncbilek) in a swept fixed bed reactor connected with a thermo-balance was performed at a heating rate of 3 degrees C/min up to 950 degrees C under 0.5MPa, IMPa and 10MPa hydrogen pressures. The formation rates of gaseous hydrocarbons, carbon oxides, water and tar were determined. The difference between the weight loss due to tar formation of the non-condensable total and the weight loss of the sample recorded continuously with the thermo-balance showed the corresponding curve of tar formation rate as a function of temperature. It was shown that the total conversion and the formation rate of the products during hydropyrolysis could be influenced by varying the pressure. On the other hand, the volatile matter evolved during pyrolysis was substantially increased in the presence of hydrogen and especially when elevated hydrogen pressure was used. (c) 2004 Elsevier Ltd. All rights reserved.