Hybrid energy-harvesting device driven by membrane-based CO2 capture

Abstract

A primary focus among researchers is to reduce the energy required for CO₂ capture. Here, we report a system designed to capture CO₂ while simultaneously generating electricity. The reaction heat of amine-CO₂ in the point-source CO₂-capture process is harvested. Amine-functionalized mixtures (TEPA-SBA/MEA+PZ) exhibit 52% higher reaction enthalpy compared to primary amine absorbents. A membrane composed of tetraethylenepentamine-impregnated poly(ethylene glycol) dimethacrylate is employed, which selectively permeates CO₂ and minimizes heat loss by separating the flue gas channel and solvent reservoir. CO₂ working capacity of TEPA-SBA/MEA+PZ is 6.6 mmol/g under steady-state conditions of 15 mol % CO₂/N₂. Electricity can be harvested at a rate of 7.5 kJ/kg, and direct utilization of thermal energy yields 445 kJ/kg (net thermal energy consumption is 2.2 MJ/kg). While the proposed system has the potential to reduce CO₂ emissions from power plants to 0.25 ton/MWh and increase total electricity production by 0.6%, addressing device energy penalties remains a significant challenge.