Energy analysis of the cryogenic CO2 capture process based on Stirling coolers

• The energy and mass flow of the CO2 capture process are described.
• The energy consumption of the main parts in the system is theoretically studied.
• The influence of flow rate, temperature and CO2 concentration is investigated.
• The techno-economic evaluation and comparison of the system are undertaken.

In the existing coal-fired power plants, the energy penalty associated with CO2 capture process is an important challenge. For this reason, energy analysis has been widely used as a powerful tool to optimize the capture efficiency and reduce energy consumption. In our previous work, a Stirling cooler based cryogenic CO2 capture system was outlined. Process simulation and energy analysis of the system were undertaken in this research. The whole CO2 capture process is composed of three sections: pre-chilling, CO2 anti-sublimation and storage. The energy consumption of each section in the system was investigated in detail. The results show that when the flow rate of flue gas (13 vol.% CO2) is set at 5 L/min and the temperature of Stirling cooler-1, 2 and 3 is set at −30, −120 and −120 °C, respectively, the energy consumption of the pre-chilling, CO2 anti-sublimation and storage sections are 15.58thermal J/s, 30.48thermal J/s and 11.40thermal J/s, respectively. The total energy consumption of the cryogenic CO2 capture system is 57.46thermal J/s (equal to 689.52 J/L flue gas).