Synergistic Control of Amine Emissions and Material Balance for Chemical CO ₂ Capture with Novel Solvents

Chemisorption CO₂ capture is considered a backstop technology for reducing carbon emissions from industrial flue gases. While water-lean and biphasic solvents have been developed to lower energy consumption and control capture costs, however, their high organic content introduces new challenges, such as amine loss and solvent component imbalance. Herein, an innovative and feasible integrated solution─water scrubbing coupled with reverse osmosis (WS-RO)─was proposed, based on the synergistic regulation of multiphase mass transfer and separation in the complex CO₂ capture process. The pilot-scale experiments confirmed the inverse effect of solvent concentration on the reduction of energy consumption and the inhibition of amine escape: while energy consumption could be reduced to 2.47 GJ/t CO₂, the total amine emissions were up to 216 mg/m³. The multistage water washing was well validated in controlling amine escape, including aerosols and gaseous amines. Coupling with efficient washing liquid separation by reverse osmosis, amine escape could be reduced to below 1.5 mg/m³, with approximately 99% of the amine components returning to the system, ensuring material balance. This study offers a viable strategy to simultaneously address energy consumption and amine loss in novel concentrated solvents, facilitating their industrial deployment.