Carbon-Catalyzed Decomposition of Methane in the Presence of Carbon Dioxide

Catalytic decomposition of methane is considered is a prospective pro-ecological method of hydrogen production. The main drawback of this method is fast deactivation of the catalyst by an inactive carbonaceous deposit formed in the reaction. In this study, a series of experiments have been made to check the effect of the presence of carbon dioxide in the reaction system on the reduction of the catalyst deactivation. The reaction of methane decomposition was carried out in two variants for 4 h in the presence of a carbon catalyst obtained from pine wood biomass. In the first variant, CO2 and methane were alternately dosed into the reaction system, while in the second variant, CO2 and methane were introduced simultaneously. The second variant reaction was performed at three temperatures, 750, 850, or 950 degrees C, and for the reaction mixture containing 5-50% CO2, while in the first variant reaction, the methane decomposition and the catalyst regeneration by CO2 were carried out at the same (750, 850, or 950 degrees C) or different temperatures. The results proved that the introduction of CO2 into the reaction system permits a considerable reduction of the catalyst deactivation, leading to an increasing content of hydrogen in the postreaction gases. The efficiency of the catalyst regeneration with CO2 introduced into the reactor simultaneously with methane is a resultant of the rates of the following main processes: carbon deposition (as a consequence of methane decomposition), gasification of the deposit and destruction of its structure by CO2, and partial gasification of the carbon catalysts.