This work was to examine Greek lignites of various origins with regard to their behaviour in a variety of gasifying media, including carbon dioxide, steam, argon or their mixtures. For this purpose a fixed bed and a fluidised bed unit were designed and constructed. Since the fluid dynamic behaviour of lignite in the various media was not established, a (1:1) cold fluidised bed model was first built with two different reactor diameters (3 and 7 cm). A factorial design investigation was employed, including the effect of lignite mass, particle size, bed diameter, bed height and distributor disk. Based on the cold model results a 1:1 hot gasifier was designed and constructed.