Friday, November 2, 2012

NETL CO2 Capture Sorbent Summary

Carbon dioxide (CO2) is considered one of the major greenhouse gases affecting climate change. An estimated one-third of anthropogenic CO2 emissions to the atmosphere results from the combustion of fossil fuels used for electricity generation. One technique for preventing CO2 emissions from entering the atmosphere is to capture and concentrate it for beneficial re-use or permanent storage in a geologic formation, assuaging a major concern with the continued use of abundant fuel sources that are domestically available.

Capture and separation of CO2 can be achieved by using solvents, cryogenic techniques, membranes, or solid sorbents. Large-scale operation of any of these technologies is energy intensive when applied to capturing CO2 from the combustion stream or flue gas, where it accounts for only about 15 percent of the volume. While wet scrubbing systems using regenerable, amine-based, solvents are the most commercially advanced, they are extremely energy intensive due in part to the large amount of processing water involved.

The NETL Basic Immobilized Amine Sorbent (BIAS) process is a "dry" sorbent-based CO2 capture technology that is both technically and economically viable for removing CO2 at low concentration from flue gas streams. The technology uses a sorbent made from an amine that is synthesized for high carbon dioxide selectivity and polymerized around a high surface area silica gel for ease of handling. The amine releases adsorbed carbon dioxide when heated at steam temperatures and can then be reconditioned as a solvent with no need for water.

Independent laboratory testing of over 100 sorbents demonstrated that NETL BIAS sorbents had the best overall performance. BIAS sorbents showed the greatest working capacity, a measure of the net ability of the sorbent to absorb CO2, were readily regenerated by heating, and had among the lowest projected regeneration energies—the amount of energy necessary to desorb CO2 from the sorbents.

An initial systems analysis indicates that solid sorbents, such as BIAS sorbents, could adsorb CO2 over a range of temperatures typically encountered downstream of flue gas desulfurization units in coal-burning power plants, and with their relatively low heat capacities would reduce the energy required for regeneration by 40 percent. Moreover, compared to state-of-the-art alternatives, BIAS sorbents are more thermally stable, exhibit little or no degradation , and produce less corrosion, eliminating the need for corrosion inhibitors. All these advantages combined to earn NETL BIAS sorbents a 2012 R&D 100 award, which recognizes 100 most technologically significant products introduced into the marketplace over the past year. Members of the award-winning NETL BIAS team are: McMahan Gray, Henry Pennline, Daniel Fauth, James Hoffman, and Kevin Resnik.

Source: NETL

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