Streamlining Carbon Capture

Carbon capture methods can cut power plant CO₂ emissions by up to 90%. But the leading technology is expensive and energy-intensive, and it requires extensive retrofits to divert power plant steam to drive the reactions. Amine solutions, which bind CO₂ in an absorption column, are steam heated in a separate chamber to regenerate the solutions by driving off the CO₂ for subsequent processing. Regenerating via an electrochemical process instead could reduce the needed retrofits and halve energy use yet retain the capture method’s effectiveness (Energy Environ. Sci. 2013, DOI: 10.1039/c3ee41165f). Developed by Michael Stern, Howard Herzog, and T. Alan Hatton of MIT, the process involves separating CO₂ from the amine solution using a device featuring copper electrodes. Applying a positive voltage releases copper ions, which bind the amines, displacing CO₂. The copper ions are recovered by reductively plating them back onto the electrode, freeing the amines for reuse. The electrically powered system, intended to be easily installed, is drawing power-company interest but would need to be scaled up, the researchers say.