Supported amine materials for CO₂ capture

Article By:

Sakwa-Novak, Miles A. School of Chemical and Biological Engineering, Georgia Institute of Technology, Atlanta, Georgia.

Jones, Christopher W. School of Chemical and Biological Engineering, Georgia Institute of Technology, Atlanta, Georgia.

Last reviewed:2014

DOI:https://doi.org/10.1036/1097-8542.YB150578

With mounting evidence that anthropogenic carbon dioxide (CO₂) emissions significantly enhance the risk of global climate change, intense efforts have been devoted to developing technologies for alternative energy and CO₂ emissions mitigation. A critical aspect of this effort is to reduce CO₂ emissions from electric power generating plants that burn fossil fuels. For the short term, one practical approach to this is retrofitting current power plants with separation units to remove the CO₂ from the plant's exhaust flue gas, a process referred to as postcombustion CO₂ capture. A schematic of this process is depicted in Fig. 1. Currently, this is practiced to a limited extent using aqueous amine gas scrubbers. Here, flue gas leaving the plant, containing 8–15% CO₂ by volume, is contacted by the amine solution so that the mildly acidic CO₂ molecules interact with the basic amines. When the solution is saturated with CO₂, it is heated to regenerate the sorbent and concentrate the CO₂ for downstream sequestration or use. Although these amine solutions remove CO₂ from the flue gas effectively, the process requires high energy input because of the large thermal mass of aqueous solution that must be heated during regeneration, ultimately resulting in a significant cost that is reflected in the price of electricity. Additionally, the amine solutions degrade under some processing conditions and are corrosive to the process equipment.

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