Syngas obtained by co-gasification of coal and wastes was hot cleaned in two catalytic reactors, which allowed destroying tar and gaseous hydrocarbons with more than one carbon atom. H(2)S and NH(3) contents were also significantly reduced, but CH(4) concentrations varying between 2% and 10% and small amounts of H(2)S (below 100 ppmv) were still found in syngas, depending on coal type and waste composition. This paper studies the effect of experimental conditions on CH(4) destruction by reforming reactions in absence and in presence of catalysts. The effect of experimental conditions (temperature, steam flow rate and syngas composition) on CH(4) destruction and on CO conversion into CO(2) in the absence of catalyst was studied first, using the Equilibrium Reactor model from CHEMKIN modelling software. The selected experimental conditions were then tested in a fixed bed reactor with and without catalyst and the results obtained were consistent with CHEMKIN Equilibrium Reactor model predictions. Commercial Ni-based catalysts were tested (G-90 B5 and G 56B from C&CS). These catalysts were capable of significantly reducing CH(4) content, by promoting reforming reactions. At the experimental conditions used and in absence of steam, G 56B seems to be more effective in CH(4) conversion, as lower CH(4) contents were obtained. In presence of steam both catalysts were capable of completely destroying CH(4). Both catalysts also promoted WGS (water gas shift) reaction to some extent, though they are not specific catalysts for this reaction. Thus, a high increase in H(2) content was observed, due to its formation by both reforming and WGS reactions. For a complete conversion of CO into CO(2) and H(2) a specific catalyst for WGS reaction is still needed. (C) 2011 Elsevier Ltd All rights reserved.