Resin Wafer Electrodeionization for flue gas carbon dioxide capture

Energy efficient capture of CO ₂ from coal-fired power plants is one of the grand challenges for the U.S. both to end dependence on imported energy and to reduce greenhouse gas emissions. Nalco Company and Argonne National Laboratory received a Department of Energy ARPA-E award to develop Resin Wafer Electrodeionization (RW-EDI) for the energy-efficient capture of CO ₂ from coal flue gas. RW-EDI is being used as an electrochemically-driven platform that switches pH in the process stream to efficiently capture CO ₂ from flue gas and then desorb it at atmospheric pressure without requiring heating, vacuum, or consumptive chemical usage. The acid/base pH shift drives the CO ₂ capture/desorption and enzymes and/or inorganic catalysts drive the targeted kinetics. The goal of the project is to demonstrate 90% capture of CO ₂ from synthetic flue gas (15% CO ₂) and 90% purity of the released stream of CO ₂. If successful, the CO ₂ capture process could significantly reduce the ∼30% parasitic energy loss associated with other capture technologies. Presented here will be recent results from a bench-scale system showing significant progress toward these goals.