Design and study of a novel ammonia-based CO2 capture process with bipolar membrane electrodialysis

Aqueous ammonia is a promising absorbent in the field of post combustion CO2 capture. However, the high volatilization of NH3 results in a high energy requirement, as well as solid precipitation during the CO2 regeneration process. A novel process was designed to reduce energy consumption and solve the problem. The bipolar membrane electrodialysis (EDBM) unit and CO2 regeneration reactor were taken as the regeneration part. In the novel process, the bubble in the EDBM unit would be eliminated, and the regeneration of CO2 and aqueous ammonia would be operated separately, which significantly reduced energy consumption and avoided the risk of precipitation during regeneration. According to the simulation and calculation results, the CO2 regeneration energy consumption of the novel process using H2SO4 for CO2 regeneration is 39.0% lower than that of the conventional ammonia-based process, which shows good energy saving potential. Moreover, the novel process will be more competitive as membrane technology develops.