Production of Hydrogen and Solid Carbon by Methane Decomposition under Pressurized Conditions Using a Rotary Reactor and Purification of Yielded Hydrogen by Hydrogen Separation Membrane

A pressurized rotary reactor was used to produce hydrogen and solid carbon through thermochemical decomposition of methane using an Fe catalyst. Here, the ratio of (CH4 flow rate)/pressure was kept constant. Pressurized conditions caused a lower initial methane conversion, but the decrease in methane conversion over time was suppressed, and the conversion was ultimately higher than that at ambient pressure after a long reaction time. The deposited carbon was formed as carbon nanofibers and carbon nano-onions. At higher pressure, the crystallinity of the deposited carbon also slightly increased. Unreacted methane, CO, and CO2 may coexist in the exhaust gas in addition to the product hydrogen. In this study, the purification of hydrogen was carried out by introducing the product gas obtained from the reaction at 5 atm directly into the commercially available hydrogen separation membrane.