Combined experimental and computational study for the electrode process of electrochemically mediated amine regeneration (EMAR) CO2 capture

Abstract

The electrochemically mediated amine regeneration (EMAR) for CO2 capture presents a promising CO2 capture approach. However, there is a lack of systematic research on the EMAR electrode process, particularly regarding the diffusion of Cu2+ and [Cu-Am]2+, the characteristics of electrode reactions, and the impact of desorbed CO2 bubbles on electrode process. In this work, we investigated the Cu-EDA based EMAR process by the combination of electrochemical measurements and multi-physics simulation. The experimental results revealed that the anode process is controlled by both mass transfer and charge transfer process, while the mass transfer process in the cathode process is the rate-controlling step. A lower anode copper loading and a higher cathode copper loading are conducive to the EMAR process. A reasonable simplification method for the electrode process was proposed by referencing the equilibrium reactive model results of Cu(II)–EDA–CO2–H2O system. A multi-physics model was constructed using COMSOL software, which coupled the Tertiary Nernst-Planck model and the Bubbly Flow model to simulate the complex electrode process and its effectiveness has been verified. Simulation results show that the formation of CO2 bubbles has a negative impact on the electrode process, while the disturbance caused by the bubbles may have a certain promotion effect on the electrode process. The CO2 desorption and the desorption rate is greatly affected by the the applied potential, and the desorption energy consumption mainly keeps a linear relationship with the applied potential. This work supposes to provide an effective guidance for the improvement of the vital electrodes process of the EMAR system.