Cold plasma activated CO2 desorption from calcium carbonate for carbon capture†

Abstract

This work investigates the non-equilibrium regeneration of one scalable sorbent material for carbon capture, calcium oxide, in a customized flow reactor coupled to a low-temperature atmospheric-pressure plasma source. The results show that such a plasma is capable of desorbing CO₂ from CaCO₃, with an operating temperature far below the thermal decomposition temperature of carbonate. The desorbed CO₂ is further converted to CO in situ. The energy cost is 1.90 × 10³ kWh per tCO₂, as the same order of magnitude as the state-of-the-art high temperature regeneration technology. A non-equilibrium kinetic mechanism is proposed in which CO₂ desorption is coupled into air plasma chemistry. Electron-impact reactions in air lead to the generation of vibrationally excited nitrogen and ozone. Subsequent quenching of atomic oxygen on the carbonate surface can regenerate CaO, while NO_x will pollute the surface. Compared with the previous methods used in sorbent regeneration, plasma-based technologies offer an electrified, sustainable, and low-temperature solution based on the non-equilibrium plasma chemistry. Possible scaling strategies include fluidization, flow pulsation, and plasma catalysis. This work demonstrates the feasibility of non-equilibrium plasma processing of the sorbent material for cyclic capture and regeneration in atmospheric air using thermally low-intensity processes.