UC Berkeley

A significant part of the cost for carbon capture and storage (CCS) is related to the compression of captured CO₂ to its supercritical state, at 150 bar and typically 99% purity. These stringent conditions may however not always be necessary for specific cases of carbon capture and utilization (CCU). In this manuscript, we investigate how much the parasitic energy of an adsorbent-based carbon capture process may be lowered by utilizing CO₂ at 1 bar and adapting the final purity requirement for CO₂ from 99% to 70% or 50%. We compare different CO₂ sources: the flue gases of coal-fired or natural gas-fired power plants and ambient air. We evaluate the carbon capture performance of over 60 nanoporous materials and determine the influence of the initial and final CO₂ purity on the parasitic energy of the carbon capture process. Moreover, we demonstrate the underlying principles of the parasitic energy minimization in more detail using the commercially available NaX zeolite. Finally, the calculated utilization cost of CO₂ is compared with the reported prices for CO₂ and published costs for CCS.