CO2 capture from atmospheric air via consecutive CaO-carbonation and CaCO3-calcination cycles in a fluidized-bed solar reactor

A thermochemical cyclic process and associated reactor is presented for the continuous removal of CO2 from ambient air via consecutive CaO-carbonation and CaCO3-calcination steps using concentrated solar energy as the source of high-temperature process heat. A fluidized-bed solar reactor is applied to accomplish the carbonation at 365–400 °C and the calcination at 800–875 °C, with reacting particles directly exposed to high-flux solar irradiation. Water vapor was introduced during the carbonation step to enhance its kinetics. Five consecutive cycles were performed, yielding complete removal of CO2 from a continuous airflow containing 500 ppm of CO2 within a residence time of 1.3 s during each carbonation step, and subsequent complete release of CO2 and regeneration of the CaO reacting particles during the calcination step. The reactor design, set-up, and experimentation using a high-flux solar simulator are described.