(515d) Water Lean Amine-Based Solvents for Carbon Dioxide Capture

Carbon dioxide released from large point sources such as coal powered plants should to be captured, stored or utilized for environmental sustainability. In order to achieve this goal, many CO₂ capture technologies have been developed, with the most advanced being aqueous amine-based solvent process. These aqueous amine solvents have low CO₂-rich viscosity, fast kinetics, and favorable thermodynamics. Deployment of these aqueous amine solvents to market is limited by high regeneration temperature due to the high heat capacity of water. To address this limitation our group and others have developed water-lean solvent systems. PNNL has developed water-lean amine-based solvents utilizing key fundamental learnings from multiple solvent chemistries. These amine-based solvents have high gravimetric CO₂ capacity (12-15 wt% ) and form liquid carbamates with significantly lower CO₂-rich solvent viscosities (~100 cP) and were regenerated at low temperatures (80-100 °C). These solvents can be recycled over multiple CO₂ absorption and regeneration cycles without significant evaporative loss or degradation. Herein we will discuss the molecular design, synthesis, characterization and testing of these amine solvents.