Identifying thermal effects in an innovative thermally-electrochemically co-driven electrochemically mediated CO2 capture system

The integration of renewable electricity and low-grade waste heat with electrochemically mediated amine regeneration (EMAR) presents a viable pathway toward developing sustainable and economically feasible CO2 capture technology. Clarifying the thermal effects of the thermally-electrochemically co-driven EMAR process is critical for optimizing system energy efficiency, particularly for large-scale industrial applications. This study investigates the thermal impacts on CO2 absorption properties, electrolyte characteristics, electrochemical behavior, and regeneration efficiency of the proposed system, using a combination of thermodynamic calculations and experimental methods. Experimental data demonstrate that the absorption temperature of 40 °C is optimal for achieving superior CO2 absorption kinetics and maximizing the absorption load. Furthermore, elevated temperatures significantly reduce electrolyte viscosity, enhancing ion diffusion and lowering overall system impedance. This facilitates improved efficiency in both oxidation and reduction reactions within the electrochemical cells, markedly enhancing overall electrochemical performance. For the desorption performance, when the temperature increased from 20 °C to 80 °C, the minimum theoretical thermodynamic energy consumption is reduced by 5.02 %. More strikingly, experimental results indicate a substantial 60.9 % reduction in practical energy consumption, dropping from 102 kJ/mol to 39.9 kJ/mol, signifying a dramatic improvement in the energy utilization efficiency of the CO2 desorption process. Considering the typical temperature of waste heat from factories, heat exchange efficiency, and the volatility of the solution, 60 °C is the recommended desorption temperature. These findings demonstrate the feasibility of the proposed thermally-electrochemically co-driven EMAR process and provide a guidance for determining the operating temperature of CO2 absorption and desorption processes, which may establish an environmentally sustainable and economically viable solution to support global carbon neutrality.