Laboratory to bench-scale performance evaluation of a biphasic solvent for low-concentration CO2 capture from simulated gas turbine flue gas

Biphasic solvent maintains over 92% CO 2 capture efficiency in 168 h operation. • D4M2 achieves 25% regeneration energy reduction compared to MEA at lab scale. • Pilot-scale validation yields 2.7 GJ/t CO 2 , 37% lower regeneration energy than MEA. • Stable viscosity and phase separation maintained throughout 168 h operation. Liquid-liquid phase change absorbents have attracted increasing attention for energy-efficient capture of low concentration CO 2 flue gas, yet most evaluations remain limited to batch experiments, with few studies conducted on continuous integrated platforms. In this study, a multicomponent amine phase change absorbent (DMAPA-MAE-DMCA-DMSO-H 2 O) was developed for gas turbine flue gas containing approximately 4 vol% CO 2 and high oxygen levels. Following batch screening, the optimal formulation (D4M2) was identified and evaluated in a 5 Nm 3 /h continuous flow system over 168 h. Capture efficiency, regeneration energy consumption, and operational stability were systematically assessed and compared with 30 wt% MEA. At a L/G ratio of 2.1 L/m 3 , D4M2 maintained a CO 2 capture efficiency above 90% with a regeneration energy consumption of 3.73 GJ/t CO 2 , representing a 25% reduction relative to MEA. During 168 h of operation, capture efficiency remained above 92%, regeneration energy was stable at 3.6–3.8 GJ/t CO 2 , and phase separation behavior showed no significant degradation. Scale-up to a 15 Nm 3 /h pilot system further reduced regeneration energy to 2.68 GJ/t CO 2 at an optimized L/G ratio of 1.8 L/m 3 , corresponding to a 37% reduction compared with MEA while maintaining capture efficiency above 90%. These results demonstrate the strong energy-saving potential and scalability of the developed phase change absorbent for CO 2 capture from gas turbine flue gas.