Post-combustion CO2 capture process in a circulated fluidized bed reactor using 200 kg potassium-based sorbent: The optimization of regeneration condition

The Potassium-based dry sorbent CO2 capture process can selectively capture CO2 from flue gas without toxicity. In this study, the optimization of regeneration condition was investigated to pursue economical CO2 capture process in a circulated fluidized bed reactor as most energy for CO2 capture is consumed in the sorbent regeneration. One important part for CO2 capture process is to produce highly concentrated CO2 during the sorbent regeneration in the conditions of CO2 rich with a presence of H2O, which thermodynamically reduces the sorbent regeneration efficiency at low temperature. This could be overcome by increasing the regeneration temperature although the sorbent regeneration energy increases. The dry sorbent performance in the carbonator was evaluated by changing the temperature, CO2 and H2O concentration in the regenerator, which showed about 88% CO2 removal efficiency and 5.6 wt% dynamic sorption capacity. The dry sorbent was sampled at each operating condition to confirm the dry sorbent performance, evaluated over CO2 concentration. The optimal regeneration condition was obtained by considering CO2 removal efficiency, dynamic sorption capacity and regeneration energy. Finally, the optimal regenerator temperature was determined to be approximately 468 K where the CO2 capture process in the circulated fluidized bed reactor showed 95% for CO2 purity.