Carbon Dioxide Thermodynamics, Kinetics, and Mass Transfer: Aqueous Amine Solvents for CO2 Capture

To screen amine solvents for application in CO2 capture from coal-fired power plants, the equilibrium CO2 partial pressure and liquid film mass transfer coefficient were characterized for CO2-loaded and highly concentrated aqueous amines at 40 – 100 °C over a range of CO2 loading. Promising solvents with large CO2 capacity, fast mass transfer rate and moderately high heat of absorption were identified. A rigorous thermodynamic model was developed for a selected amine solvent in the framework of the Electrolyte Nonrandom Two-Liquid model using the vapor-liquid-equilibrium and liquid speciation data. The lab-scale mass transfer rate data was represented with a rate-based model created in Aspen Plus®, in which the reaction rate was described with activity-based termolecular mechanism. The rate-based model can be used for design and simulation of large-scale CO2 capture process.