Performance analysis of a hybrid system combining cryogenic separation carbon capture and liquid air energy storage (CS-LAES)

Cryogenic separation carbon capture is a promising green carbon emission reduction approach, which is rarely applied due to its high cold energy requirement. This work proposes a hybrid system combining cryogenic separation carbon capture and liquid air energy storage (CS-LAES), comprehensively utilizing low-temperature and high-pressure conditions of LAES to reduce the energy consumption of cryogenic CO₂ separation. Flue gas with higher carbon dioxide (CO₂) concentrations from coal-fired power plants is compressed in the charging process of CS-LAES instead of air. The CO₂ is captured, and the CO₂-free air is liquefied and stored for later use. The results demonstrate that the carbon capture energy consumption of the CS-LAES system is 1.12 GJ/ton, which is 0.68 GJ/ton lower than that of conventional cryogenic capture technology (1.80 GJ/ton). The CO₂ capture rate of 99.97 % is higher than that of most existing cryogenic CO₂ capture technologies. Moreover, the standalone total exergy efficiency (S_TEE) for energy storage of the CS-LAES system was 63.40 %, which is 5.22 % higher than the baseline LAES. Meanwhile, the dynamic payback period of the CS-LAES system is 5.82 years, which is more economical than that of baseline LAES (12.89 years) due to avoiding expensive carbon tax.