In synthetic natural gas (SNG) reaction process, the water gas shift (WGS) reaction and methanation reaction take place simultaneously, and an insufficient supply of steam might deactivate the catalyst. In this study, the characteristics of the methanation reaction with a commercial catalyst and using a low [H-2]/[CO] mole ratio in SNG synthesis are evaluated. The reaction characteristics at various possible process parameters are evaluated varying different process parameters such as the [H2O]/[CO] mole ratio, [H-2]/[CO] mole ratio, flow of different % CO2, and reaction temperature. Temperature profiles on catalyst bed are monitored as a function of the [H2O]/[CO] mole ratio, [H-2]/[CO] mole ratio, and flow of different % CO2. Through a lab-scale optimization process, suitable optimum conditions are selected and in the same condition a 50-kW pilot-scale SNG production process through adiabatic reactors is carried out. The pilot scale SNG reaction is stable through overnight and the CO conversion efficiency and CH4 selectivity are 100% and 97.3%, respectively, while the maximum CH4 productivity is 0.654m(3)/kg(cat) . h. Copyright (C) 2016 John Wiley & Sons, Ltd.