Selective methanation of carbon monoxide over Ru-based catalysts in H2-rich gases

A series of Ru/Al2O3 methanation catalysts containing 0.5–5.0% Ru were prepared by impregnation. This study was designed to investigate the optimization conditions and catalytic activities for the selective methanization of carbon monoxide in hydrogen-containing streams, by use of a catalytically active composition which comprises ruthenium as the active component and a support material based on aluminum oxide. The properties of the catalysts were characterized by XRD, TG and SEM technique. A number of laboratory experiments were performed to clarify the influence of process parameters (Ru loading, calcinations temperature, space velocity and chlorine ions content) on the activities of catalysts. The experimental results showed that the application of ultrasound impregnation could significantly decrease impregnation time and improve the activity of catalyst. The optimum process preparation conditions for these factors were found to be space velocity 3000 h−1, calcination temperature 400 °C and 2% Ru loading, respectively. Under these conditions, the CO conversion and CH4 selectivity were 97.2% and 83.3%. The catalyst washed with deionized water and diluted ammonia not only removed chlorine, but also improved the catalytic activity. Overall, the catalyst showed high performance at optimization preparation conditions, and its activity was maintained after 4320 min. It was a promising candidate for utilizing H2-rich gas to produce methane at a wide temperature window.