An improved fast screening method for single and blended amine-based solvents for post-combustion CO2 capture

• An improved screening method was developed with initial lean loading and time limitation for absorption/desorption process.
• Screening result of single amines was validated by simulation experiments in Aspen Plus.
• The method was applied for optimal molar ratio selection for blended amine systems.

An improved fast screening method, i.e. the multiple fast screening method, was developed to quickly screen high efficiency solvents for post combustion CO2 capture, especially for the existing amine-based CO2 capture processes. The method was based on an integrated CO2 absorption-desorption process, where the absorption process was performed at 40 °C with a certain initial lean loading, obtained by a pretreatment process, and desorption process is done at the temperature of 80 °C. The duration of each of the two processes was set to be 60 min. This screening method, taking into account the CO2 absorption capacity as well as the absorption and desorption efficiency, was tested on five single alkanolamines in aqueous solutions with concentration of 30 wt%, and blended MEA/DEEA solutions with different ratio at a certain total molar concentration of 5 mole/L. The repeatable screening results of the single amines by this improved method show that the cyclic capacities of the amines are different from the experimental results obtained by using the equilibrium-based screening method, the experimental results of single amine solutions were finally further validated by a simulation process in Aspen Plus and show good agreement. For the blended amine systems screening, the molar ratio of MEA/DEEA of 2.5:2.5 presents the highest cyclic capacity, while no optimal ratio is found by using traditional equilibrium-based screening method. The absolute average difference (AAD) of mass balance between gas and liquid phases for both the single and blended amines screening experiments was calculated, and it turns out to be reliable with the value of 2.65% and 2.80%, respectively.