Surfactant-Modified monoethanolamine for better foaming to enhance CO₂ removal efficiency

This study investigated the foaming modification and reaction mechanism of monoethanolamine (MEA) using surfactants, and systematically evaluated the performance of a multi-flow CO₂ absorption tower under different operating conditions through orthogonal experiments. The experimental results show that the addition of AEO-7 significantly reduces the surface tension of MEA (by 35 %-42 %), promotes foaming, and reduces mass transfer resistance, thereby increasing the absorption efficiency by 17 %–32 %. Through in-depth investigation of the reaction mechanism using ¹³C NMR and FTIR techniques, it was found that AEO-7 improves the foaming characteristics of MEA solutions physically, significantly enhancing CO₂ removal efficiency without directly altering the chemical reaction pathway of MEA. The optimal operating conditions determined by range analysis are: gas flow rate of 60 L/min, liquid flow rate of 500 ml/min, CO₂ concentration of 8 vol%, and MEA concentration of 20 wt%. Under these conditions, the overall absorption efficiency in the tower increased by more than 43.42 % compared to the least favorable conditions, providing scientific evidence for the design and operation of absorption towers and revealing the optimal operating parameter combination under the interaction of multiple factors, effectively enhancing CO₂ removal efficiency.