Production of high purity CO₂ from air using solid amine sorbents

For CO₂ capture from air on a supported amine sorbent, the effects of water co-adsorption and steam purge on the CO₂ working capacity and energy requirement for CO₂ desorption are studied. Working capacities are studied by fixed bed operation for changing temperature, pressure and amount of steam purge. Results show that for pressure-temperature swing adsorption a temperature above 100 °C and a pressure below 200 mbar as desorption conditions are required to maximize CO₂ working capacity and reduce energy requirement for desorption. Co-adsorption of water reduces energy requirement due to an increased CO₂ working capacity. Application of a steam purge increases the CO₂ working capacity and hence reduces sorbent inventory required. However, the net energy requirement per kilogram CO₂ does not decrease due to the latent heat of water. Concluding, steam purge regeneration for air capture does not reduce opex but might reduce capex.