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/molCO2, which is 52.0% higher than that of 30 wt% aqueous monoethanolamine solution. Thermal energy harvesting density is estimated as 202.2 kJ/kgsolvent 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 tCO2/MWhe with thermal energy production of 751 kWh/tCO2, which can contribute to 51.9% reduction in the operational energy.