CO2 capture performance, kinetic and corrosion characteristics study of CO2 capture by blended amine aqueous solutions based on 1-(2-hydroxyethyl) piperidine

The chemical absorption method using amine-based aqueous solutions as absorbents is considered a critical technology in the mitigation of CO₂ emissions. However, the trade-off between absorption performance and energy consumption presents a significant challenge for large-scale industrial applications. In this study, we propose using N-(2-hydroxyethyl)ethylenediamine (AEEA), 1-(2-amino Ethyl)piperazine (AEP) and piperazine (PZ) to regulate the CO₂ capture characteristics of 1-(2-hydroxyethyl)piperidine (HEP) aqueous solution. We found that the addition of promoter AEEA/AEP/PZ increases the CO₂ absorption and desorption performance of HEP aqueous solution. We established the CO₂ capture mechanism, which involves the generation of HEPH⁺, carbamate, and bicarbonate during the absorption of CO₂. During the desorption process, the bicarbonate can be decomposed, while the carbamate remains in the solution. Furthermore, we obtained data on the kinetics and corrosion characteristics of the blended absorbents. The absorption resistance of the three blended amine aqueous solutions is concentrated on the gas film, accounting for approximately 77 %. The corrosion rate of blended amine-enriched solutions on 20# carbon steel decreases with the increasing mass fraction of promoters or CO₂ loading. SEM-EDS analysis revealed the presence of a dense FeCO₃ oxide film on the surface of 20# carbon steel, which protects the carbon steel sheet from further corrosion. Overall, the proposed absorbents indicated a promising potential in the CO₂ capture applications.