Novel CO2 Solvent System for Fast CO2 Capture From Post-Combustion Flue Gas

Wet scrubbing is one of the most mature technologies that can be commercialized for post-combustion CO₂ capture in the near term. The major obstacle in the development of such technology to commercial-scale carbon capture is the high capital and operating cost using the state-of-art solvent system, such as aqueous monoethanolamine (MEA) system. The novel blend solvent (CAER-B5) developed in the Center for Applied Energy Center at the University of Kentucky has the advantages of fast CO₂ removal rate, high carbon cyclic loading, high thermal stability, low volatility, and commercial quantity available. The development of the CAER-B5 could largely reduce the energy requirement and capital cost for CO₂ capture. Tests on wetted-wall column at simulated scrubber condition indicates that the CO₂ removal rate of CAER-B5 solvent is 50% higher at lean loading and 30% higher at rich loading than those of 30 wt% MEA. Such high removal rate helps reduce the size of absorber. The heat of absorption derived from the vapor liquid equilibrium data suggests that the energy required for CO₂ regeneration is approximately 10% less than that of aqueous MEA system. Thermal stability study performed at 125 ¡ãC and 135 ¡ãC shows that CAER-B5 can be operated at about 10 ¡ãC higher than that of 30 wt% MEA at given similar degradation rate. Operating at elevated temperature increases the CO₂ partial pressure at the top of stripper, lowering process energy by reducing the steam to CO₂ ratio and auxiliary energy for CO₂ compression.