Integrated Capture and Conversion of CO<sub>2</sub> to Methane Using a Water‐lean, Post‐Combustion CO<sub>2</sub> Capture Solvent
Jotheeswari Kothandaraman, Johnny Saavedra Lopez, Yuan Jiang, Éric Walter, Sarah Burton, Robert A. Dagle, David J. Heldebrant
Abstract
Abstract Integrated carbon capture and conversion of CO 2 into materials (IC 3 M) is an attractive solution to meet global energy demand, reduce our dependence on fossil fuels, and lower CO 2 emissions. Herein, using a water‐lean post‐combustion capture solvent, [ N ‐(2‐ethoxyethyl)‐3‐morpholinopropan‐1‐amine] (2‐EEMPA), >90 % conversion of captured CO 2 to hydrocarbons, mostly methane, is achieved in the presence of a heterogenous Ru catalyst under relatively mild reaction conditions (170 °C and <15 bar H 2 pressure). The catalytic performance was better in 2‐EEMPA than in aqueous 5 m monoethanol amine (MEA). Operando nuclear magnetic resonance (NMR) study showed in situ formation of N ‐formamide intermediate, which underwent further hydrogenation to form methane and other higher hydrocarbons. Technoeconomic analyses (TEA) showed that the proposed integrated process can potentially improve the thermal efficiency by 5 % and reduce the total capital investment and minimum synthetic natural gas (SNG) selling price by 32 % and 12 %, respectively, compared to the conventional Sabatier process, highlighting the energetic and economic benefits of integrated capture and conversion. Methane derived from CO 2 and renewable H 2 sources is an attractive fuel, and it has great potential as a renewable hydrogen carrier as an environmentally responsible carbon capture and utilization approach.