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.