Evaluation of potassium glycinate, potassium lysinate, potassium sarcosinate and potassium threonate solutions in CO2 capture using membranes

The mitigation process of greenhouse gases emission such as CO2 into the atmosphere is known as a vital necessity in modern societies. Nowadays, amino acid salt solutions (AASSs) have been extensively applied as a promising alternative to alkanol amine absorbents to increase the CO2 sequestration efficiency from disparate gaseous flows. This article aims to computationally and theoretically evaluate the CO2 separation percentage using potassium glycinate (PG), potassium lysinate (PL), potassium sarcosinate (PS) and potassium threonate (PT) amino acid solutions from an inlet gaseous mixture inside a hydrophobic membrane contactor (HMC). To do this, the governing first principal equations inside the HMC are solved using the computational fluid dynamics procedure based on finite element technique. Acceptable agreement between the simulation results and experimental values with average deviation of approximately 3% implies the validation of developed two-dimensional (2D) simulation approach developed in this study. The analysis of obtained results demonstrated that PG is the most efficient amino acid solution for CO2 molecular sequestration with the ability of separating 90% of inlet CO2 in the system. The order of solutions is 90% sequestration using PG > 89.3% sequestration using PT > 77.4% sequestration using PL > 72.3% sequestration using PS.