Biomethane produced by catalysis of green hydrogen and carbon dioxide can be incorporated into existring energy processing systems. Recently, as the desire to transition to a green and sustainably independent energy economy grows, research on such technologies is growing. Thermal phenomena during methanation in catalytic reactor is not well researched yet, therefore in our work, we examine the process of developing and building experimental setup for infrared thermograohic observation of catalytic methanation. With the help of a developed experimental setup, we performed measurement of the unsteady temperature field during the catalytic methanation process. We examined the operation of the designed reactor at different temperature conditions, reactant gas flows and type of catalysts. Because of methanation process the temperature of individual pelets of catalysts where reaction takes place increases, which can be effectively monitored using infrared thermography.