Sustainable energy harvesting from post-combustion CO₂ capture using amine-functionalized solvents

Energy consumption during the post-combustion CO₂ capture process is significant, which decreases energy efficiency of industrial power plant. Many studies have been conducted to increase the CO₂ capture capacity and reduce thermal energy duty by utilizing a new material instead of the amine-based CO₂ absorbent or by optimizing the system. However, vast energy is still consumed in the regeneration process. Herein, sustainable thermal energy harvesting system from post-combustion CO₂ capture (15 vol% CO₂ and 85% N₂ at 20 °C and 1 bar) has been proposed. The functionalized solvent, composed of tetraethylenepentamine-impregnated mesoporous silica (TEPA/SBA-15) and blended chemical aqueous absorbent (MEA + PZ), is developed to maximize thermal energy harvesting density and selective CO₂ capture capacity. The reaction heat of solvents reaches 124.6 kJ/mol_CO2, which is 52.0% higher than that of 30 wt% aqueous monoethanolamine solution. Thermal energy harvesting density is estimated as 202.2 kJ/kg_solvent during CO₂ capture process. When the functionalized solvent is applied to the industrial post-combustion CO₂ capture system of thermal power plants, CO₂ emission is reduced to 0.210 t_CO2/MWh_e with thermal energy production of 751 kWh/t_CO2, which can contribute to 51.9% reduction in the operational energy.