Synthetic CaO-Based Sorbent for CO2 Capture from Large-Point Sources

The main impetus for future technology development for capturing and purifying CO2 from industrial flue gases is the potential for minimizing the cost of capture and reducing the efficiency penalty that is imposed on the process. Carbonate looping is a very promising future technology, which uses CaO-based solid sorbents, with great potential to reduce the cost of capture and lessen the energy penalty compared to closer to market technologies, e.g., solvent scrubbing. Unfortunately, the CO2-capture capacity of a CaO-sorbent derived from natural limestone decays through long-term capture-and-release cycling; thus, the development of strategies and/or novel sorbents to achieve a high CO2-capture capacity is an important challenge for realizing the cost efficiency of carbonate looping technology. To this end, we report on the development and characterization of a novel synthetic CaO-based sorbent produced via a precipitation method and present experimental results demonstrating improved long-term CO2-capture capacity based on reactivity testing using a thermogravimetric analyzer (TGA) and a bench-scale bubbling fluidized-bed (BFB) reactor. We achieve a capture capacity of about 2.5 times the amount of CO2 after 15 cycles with the synthetic sorbent compared to a natural limestone (Havelock) in the BFB.