Ru/K2CO3–MgO catalytic sorbent for integrated CO2 capture and methanation at low temperatures

In this study, we have developed a Ru/K2CO3–MgO (Ru/KMg) catal-sorbent for integrated CO2 capture and methanation (ICCM) at low temperatures. The Ru primarily existed as a K2RuO3 phase, which was not observed after reduction at 400 °C. In addition, the crystallite size of Ru0 is smaller than that of Ru/MgO because Ru species as K2RuO3 phase, instead of RuO2, is dispersed well throughout the MgO support material. Here, the CO2 capture and regeneration properties of Ru/KMg catal-sorbents after carbonation at different temperatures (60, 120, 150, and 320 °C) were studied under N2 or H2 conditions, respectively. The optimal carbonation temperature was 150 °C when considering 100% CO2 conversion to CH4. 20 consecutive cycles of ICCM were conducted at 150 °C for carbonation (10 vol% CO2 and 10 vol% H2O) and 320 °C for methanation (90 vol% H2). The results showed stable CH4 productivities of 1.07–1.19 mmol CH4/g with 100% CH4 selectivity and 96.2%–101.3% CH4 yield.