Membrane-based CO₂ absorption into blended amine solutions

A blended solution based on amino acid salt was presented as a CO₂ absorbent. Coupling process of a membrane contactor and the blended solution was investigated. The performances of the blended solution were experimentally compared with the single amino acid salt solution. Effects of various factors such as gas and liquid flow rates on CO₂ concentration at gas and liquid outlets, capture efficiency, and overall mass transfer coefficient were discussed. A resistance in series model was developed to predict the overall mass transfer coefficients. Results show that performance of the blended solution is evidently better than that of the single solution. The blended solution can give lower CO₂ concentration at gas outlet and higher CO₂ concentration at liquid outlet as well as higher capture efficiency when compared with the single solution. The overall mass transfer coefficient with the blended solution is much higher than that with the single solution. The blended solution is confirmed to be an efficient absorbent for CO₂ capture in membrane gas absorption. Model values are in good agreement with the experimental values.