Abstract: High energy consumption and large cooling water consumption are the bottlenecks of chemical absorption technology for carbon dioxide (CO₂) capture from flue gas. Using the biphasic solvent for CO₂ capture is a promising technology in significantly reducing the regeneration energy as the biphasic solvent enables phase separation spontaneously after CO₂ absorption and CO₂ is rich in one phase. This paper used an aqueous blend of diethylaminoethanol (DEEA, 50%) and monoethanolamine (MEA, 25%) as novel biphasic solvent, and built a 150 000 t/year CO₂ capture process on Aspen Plus. Based on experimental data, DEEA's electrolyte non-random two liquids (eNRTL) thermodynamic model was established to solve the problem of lack of physical properties. Results show that DEEA/MEA process shows can be reduced by 31% lower regeneration energy, 30% lower solution circulation flux, and 17% lower water consumption than MEA process at 90% of CO₂ removal efficiency. The lowest regeneration energy of DEEA/MEA process is 2.69 GJ/tCO₂. The DEEA/MEA process has a 10% lower capital cost and a 15% lower operating cost than MEA process. The simulation results are of reference value for industrial design.