Lowering the energy consumption in the electro-regenerative process of an alkaline solvent for carbon capture

According to the IPCC's special report from 2018, global warming is expected to reach 1.5°C between 2030 and 2052 if it continues to increase at the current rate. Greenhouse gas emissions are unequivocally accountable to human activities, with global surface temperatures already reaching 1.1°C between 2011 and 2020. Given the above, one of the major objectives of the European Union's energy strategy is to reduce greenhouse gases, such as CO2, which absorb and release thermal infrared radiation, causing the Earth's temperature to rise. Therefore, the reduction of CO2 emissions has become one of the priorities for highly developed countries as well as sectors of private industry around the world. In this scenario, carbon capture, utilization, and storage (CCUS) is a promising approach for mitigating climate change. Carbon capture and utilization, in particular, promote a circular cycle and the production of valuable new products such as chemicals and synthetic biofuels. Several studies have been carried out concerning the separation of CO2 from the solvent employed for capturing it. However, the technologies' practical scalability is limited by significant energy demands associated with CO2 desorption and solvent regeneration. To address these challenges, this work proposes an innovative electrochemical process based on anion exchange membranes (AEMs) for CO2 separation and alkaline solvent regeneration. During the study, the performance of the system was analyzed under different operating conditions through two key parameters, namely the current yield and the energy consumption. The system has demonstrated to achieve current yields of 99% and minimum energy consumption of 21 kJ/molCO2. These values are noteworthy when compared to the state-of-the-art thermal cycle for solvent regeneration being around 236 kJ/molCO2. The parameters influencing the system's resistance were then examined by constructing a polarization curve and measuring the resistances of the electrochemical cell's components. This examination identified 16% of the contribution to the ohmic resistances, encouraging further research. Furthermore, the positive contributions to energy consumption have been deepened through the study of the spontaneous diffusion of the desired chemicals through the membrane and the advantageous buffer effect. Finally, a stability analysis was performed to verify the system's controllable and steady outflow of the (CO2+H2) gas mixture in the correct ratio to be supplied to a synthetic methane production station. Some degradation tests have been conducted in this context, leading to the conclusion that no major degradation occurs in the system.