Reactive Absorption of CO2 from Industrial Flue Gas Using Aqueous Solution Containing Renewable Prepared Amine

Flue gas from coal-fired power plants, cement manufacturing, refineries, etc., is considered as one of the major sources of CO₂ emissions which contribute to the increasing greenhouse effect. Because of this adverse effect of CO₂ discharge on the global environment, as well as the world’s immense dependence on fossil fuels, the development of strategies for the reduction of CO₂ emissions has become increasingly important. With this viewpoint, considerable efforts are underway towards the development of CO₂ capture technologies. Due to its higher efficiency and lower complexity, amine based closed loop chemical absorption/desorption technology (CADT) is preferred industrially as an effective gas sweetening process for separation of CO₂ from flue gas. In this investigation, solvent-1: aqueous solution of renewably prepared ethylaminoethanol (EAE), solvent-2: aqueous blend of EAE and N-methyl-2-pyrolidone (NMP), and solvent-3: aqueous blend of EAE, NMP, and hydroxyl radical scavengers were investigated towards reactive absorption of CO₂ from industrial flue gas. Degradation of all the above mentioned solvents in presence of O₂ and CO₂ was studied at different experimental conditions by using a high-temperature high-pressure subcritical reactor and the samples obtained after performing the degradation reactions were analyzed via gas chromatography (GC). Furthermore, kinetics of reactive absorption of CO₂ in solvent-1, solvent-2, and solvent-3 was also investigated in detail by using stirred cell reactor. A fall in pressure technique was employed for the absorption study and fall in the CO₂ pressure during the absorption experiments was determined by using pressure transducer coupled with a data acquisition system. Effects of various process parameters such as stirring speed, amine concentration, and reaction temperature on absorption kinetics were examined in detail. The results obtained indicate that solvent-1, solvent-2, and solvent-3 possess relatively high solvent stability and CO₂ absorption capacity with faster absorption kinetics as compared to previously investigated amine based solvent systems. The experimental set-up/procedures and results obtained during this investigation will be presented in detail.