Kinetics study of CO₂ absorption into methyldiethanolamine, potassium lysinate, and their blends in aqueous solution

Abstract

In this work, the kinetics for the reaction of CO2 with three chemical solvents were studied experimentally and theoretically. The CO2 absorption flux into the potassium lysinate (K‐Lys), methyldiethanolamine (MDEA), and their blends was measured over the CO2 partial pressure range of 50–500 kPa, and at temperatures 298.15, 303.15, and 313.15 K using a stirred cell reactor. The effect of the addition of K‐Lys on the absorption flux of CO2 into MDEA solution at low and high pressure was investigated. The reaction kinetics of CO2 absorption in CO2‐loaded MDEA, K‐Lys, and MDEA + K‐Lys solutions were also examined and absorption flux of CO2 as a function of CO2 loading was determined. The values of CO2 diffusivity, viscosity, the liquid mass transfer coefficient, the overall reaction rate constant, and the physical solubility of CO2 into MDEA + K‐Lys solution were reported. Furthermore, a standard kinetics model was developed to describe the CO2 absorption behavior in the solution at low and high pressures, for both unloaded and CO2‐loaded systems.