Performance characteristics of auto-methanation using Ru/CeO2 catalyst, autonomously proceeding at room temperature

Abstract

Assuming the treatment of exhaust gas from an industrial process, the methanation characteristics of a Ru/CeO2 catalyst are investigated when oxygen coexisted in the raw material gas. The change in oxygen concentration significantly affected methanation activity, and above 2 vol%, the methanation started autonomously at a room-temperature region, demonstrating auto-methanation (AM) behavior. In this case, oxygen selectively combused hydrogen and did not burn the produced methane. The start-up state and heat generation state of the AM in the room-temperature region are summarized in the mapping information using the oxygen concentration in the raw material gas and feeding flow rate as parameters. The AM that started at room temperature demonstrated constant activity and methane selectivity for a considerably long time, as well as constant methanation characteristics even during daily start-up and shut down (DSS) operations, which repeatedly starts and shuts down. The change in the surface morphology of the Ru/CeO2 catalyst in the DSS operation is insignificant. Thus, the methanation system constructed in this study is considered to be highly applicable as an industrial CO2 treatment technology.