CO2 capture and regeneration properties of MgO-based sorbents promoted with alkali metal nitrates at high pressure for the sorption enhanced water gas shift process

We investigated the CO2 sorption and desorption properties of MgO-based sorbents at pressures ranging from 1 to 20 atm. The effects of desorption gas composition on regeneration was also investigated, using temperature programmed desorption (TPD). The MgO-based sorbents promoted with alkali metal nitrate without K2CO3 had the highest CO2 capture capacity and good regeneration properties, compared to MgO-based sorbents with both nitrates and K2CO3. Alkali metal nitrates play an important role in improving CO2 capture capacity by providing channels for CO2 diffusion. The addition of K2CO3 causes sorbent aggregation, resulting in their deactivation. Also, the necessary regeneration temperature increased from 430 °C to 650 °C with an increase in the pressure and regeneration CO2 concentrations.