Salt-Composition-Controlled Precipitation of Triple-Salt-Promoted MgO with Enhanced CO2 Sorption Rate and Working Capacity

Triple-salt-promoted MgO composites (NaNO3, Na2CO3, and LiNO3) for precombustion CO2 capture were developed by a precipitation method with a controllable salt composition. MgO precursors were mixed and aged with salts to control the composition and morphology. The MgO composites exhibited a CO2 sorption capacity of 73 wt % in pure CO2 at 240 min and 300 °C and achieved a sorption capacity of 25 wt % within 10 min because of a high sorption rate. When a cyclic test was conducted with pure CO2 sorption for 60 min at 325 °C and N2 regeneration for 15 min at 425 °C (60/15 min cycle) as a reference, the cyclic capacity was 45 wt % after 30 cycles. On the other hand, considering the applicable capture processes, the sorption capacity during a fast cycle (10/5 min cycle) was 18 wt % under the same gas and temperature conditions. Finally, the working capacity of the MgO composite was evaluated under a simulated emission gas (29% CO2, 3% H2O, and balance N2) at 300 °C for sorption and CO2 at 450 °C for regeneratio...